Articles in Press

  • Simultaneous Parameter Tuning of PSS and Wide-Area POD in PV Plant using FPA (Accepted: 2019-08-09)
    Herlambang Setiadi, Universitas Airlangga
    Muhammad Abdillah, Universitas Pertamina

    In future power grid scenario, large-scale renewable energy based on power plant will be one of the main generations. Among renewable based power plant type, large-scale photovoltaic (PV) plant becoming more popular as they could provide zero emission and sustainable energy. However, even though PV plant could contribute positive impact to the environment, they could also contribute negatively to the power system. Large-scale PV generation came with different dynamic and zero inertia characteristic due to the application of the power electronic devices. Furthermore, PV plant has also drawback in terms of intermittent power output due to the uncertainty of the sources. Those handicaps could deteriorate the stability performance of power system especially oscillatory stability. Adding power system stabilizer (PSS) to the systems is one of the approaches for handling the oscillatory stability. However, with integration of PV plant in the systems, PSS alone is not enough to handle the oscillatory problems coming from various sources such us from PV plant dynamic. Hence, utilizing wide-area power oscillation damping (POD) as PV plant supplementary controller is inevitable. Hence, this paper proposes simultaneous parameter tuning between PSS and wide-area POD in PV plant using flower pollination algorithm (FPA) as the optimization method. The two-area power system is employed to evaluate the performance of PSS and POD using FPA. From the results, it is found that the proposed method could enhance the oscillatory stability of the systems

  • Analysis of Tropospheric Nitrogen Dioxide Using Satellite and Ground Based Data over Northern Thailand (Accepted: 2019-08-05)
    Pichnaree Lalitaporn, Kasetsart University
    Tharinee Boonmee, Kasetsart University

    Tropospheric NO2 columns over northern Thailand were analyzed using satellite products of the SCIMACHY, OMI, GOME-2A, and GOME-2B sensors for the 14-year period 2003–2016. The comparative results of the four pairs of different satellite datasets within overlapped years showed that they were well correlated with correlation coefficients (r) ranging from 0.82 to 0.88. The r-values improved to 0.85–0.90 when the analysis was considered only during the dry period (October to April). Ground in situ measurements of NO2 concentrations were also obtained for comparative analysis with the satellite NO2 columns. The results revealed relatively good agreement between these two parameters for a seasonal pattern. High levels of NO2 were detected by both satellite and ground monitoring during January–April with the maximum levels in March. Moreover, during this period, most satellite and ground datasets recorded greater levels of NO2 in the afternoon corresponding with the number of fire hotspots collected from the MODIS-Terra and -Aqua satellites. Satellite and ground measurements show slightly increasing annual trends of NO2 levels for 2010–2016 with values of 8.40 and 1.18 %, respectively, over the 6-year period.

  • Application of Heuristic Algorithms in Improving Performance of Soft Computing Models for Prediction of Min, Mean and Max Air Temperatures (Accepted: 2019-09-27)
    Armin Azad, Semnan University
    Jamshid Pirayesh, Semnan University
    Saeed Farzin, Semnan University
    Leila Malekani, University of Tabriz
    Sheida Moradinasab, Semnan University
    Ozgur Kisi, Ilia State University

    Traditionally, climate conditions has been one of the influential factors in population growth in worldwide. Hence, predicting these conditions can be an important step to improve life conditions in worldwide. In this study, application of genetic algorithm (GA) and particle swarm algorithm (PSO) were considered as alternatives to available algorithms for training artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) in order to predict air temperature. Therefore, monthly minimum, average and maximum air temperatures of Tehran-Iran station at 64-years (1951-2014) were selected as predicted time-series. Firstly, the most appropriate inputs were selected for models using sensitivity analysis. After that, long-term air temperatures (1 month, 1, 2 and 3 years ahead) were modeled.  Results showed that: 1) the given algorithms had acceptable results in improving the models’ performance in modeling minimum, mean and maximum air temperatures. Also, they could improve the performance of ANN and ANFIS in most of the prediction intervals, 2) ANFIS-GA was selected as the most suitable model so that its average determination coefficient (R2), root mean square errors (RMSE) and mean absolute errors (MAE) were 0.88, 1.41 and 2.52, respectively, 3) the sensitivity analysis provided suitable results in selecting the most appropriate model inputs for forecasting the minimum, mean and maximum air temperatures in different intervals.

  • Hybrid Motor System for High Precision Position Control of a Heavy Load Plant (Accepted: 2019-08-09)
    Gridsada Phanomchoeng, Mechanical Engineering Department, Chulalongkorn University, Bangkok 10330, Thailand
    Ratchatin Chancharoen, Department of Mechanical Engineering, Chulalongkorn University

    The lift up or press process with high precision position control is an important application in industries. An example of the process lift up and press is the process of a machine tool for drilling, milling, or injection. It is difficult to design the mechanism and controller to control the position of the base table accuracy because it needs to control the base position of the system with the weight varying in a large range. Also, the friction in the system would vary in a large range. This lead to low performance of the system in some range of load. Therefore, the new design system utilizes a DC motor and ball screw and pneumatic actuator to create the hybrid motor system for applying to the lift up and press system. The pneumatic actuator is designed to support the heavy load and the DC motor and ball screw is designed to control the position. Then, the developed hybrid motor can be used to improve the performance of the system. The simulation and experiment results show that the developed system can improve the rise time, setting time, and steady state error. Then, the time response of the system with heavy load look similar to the time response of the system with light load. Moreover, the developed hybrid motor technique can apply to the applications such as to control the 3D powder painter tank base position, and the silicon injection system, the 3D print head, which is a challenge system due to the high friction in tube.

  • The Experimental investigation and Numerical Analysis on Horizontal Axis Wind Turbine with Winglet and Pitch Variations (Accepted: 2019-10-18)
    Nyoman Ade Satwika, Institut Teknologi Sepuluh Nopember Surabaya

    HAWT with three blades is often used, because it has the highest power coefficient among other turbines. The airfoil used is Clark-Y type because it has high glide ratio (coefficient lift/coefficient drag) in the application of subsonic flow. The main purpose of this study is to increase the power coefficient value obtained by the increase of lift force on each airfoil of blade compiler, and to fix the wind turbine performance. One of the variations added is the addition of winglets on the tip of the blade. The method employed is laboratory scaled experiment by using Wind Tunnel. Theoretically, this study also applied Blade Element Momentum (BEM) as the calculation of each segment on airfoil, and the simulation was done by using Computational Fluid Dynamic (CFD), in order to find out the characteristics of flow passing by the rotor. The advantage of using winglets is, fostering the condition of starting wind turbine rotor on small Tip Speed Ratio (TSR) condition by varying the pitch angle on the blade. The addition of pitch variation gives an advantage that it can maximize the wind speed towards the angle of attack to airfoil, hence it increases the aerodynamic effect on the rotor.

  • Modeling of Precast Concrete Load-Bearing Walls Exposed to Fire (Accepted: 2019-10-29)
    Thanyawat Pothisiri, Professor, Department of Civil Engineering, Chulalongkorn University, Phayathai Road, Pathumwan, Bangkok 10330, Thailand
    Pitcha Jongvivatsakul, Assistant Professor, Department of Civil Engineering, Faculty of Engineering, Chulalongkorn University
    Soklin Chou, Ph.D., Advancing Engineering Consultants, Ltd., No. 23 Street 294 Sangkat Tonle, Basac, Phnom Penh, Cambodia
    Anil C. Wijeyewickrema, Associate Professor, Department of Civil and Environmental Engineering, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8552, Japan

    The performance of precast concrete load-bearing walls exposed to fire is investigated using 3-D thermal and structural models. The thermal model is validated by comparing the predicted temperatures with results from the fire tests carried out in the present study, previous experimental studies, and Eurocode 2. The structural model is validated by comparing the predicted displacements and crack patterns with results from the fire tests carried out in the present study. It is found that the results obtained from the thermal model and the structural model are in line with the experimental data and Eurocode 2 results. The validated 3-D model of precast concrete load-bearing walls is used to study the effect of load level, slenderness ratio and boundary conditions on the fire performance of the walls. The results show that the fire resistance rating of load-bearing walls decreases with increasing load level and slenderness ratio, while the fire resistance rating of the walls increases when rotational restraints are imposed at the ends of the walls. Finally, equations are presented for estimating the fire resistance rating of the walls with different support conditions.

  • Novel Approach to Respiratory Rate Measurement using Resonance Tube and TRIZ (Accepted: 2019-10-25)
    TriZit Benjaboonyazit, Thai-Nichi Institute of Technology
    Mana Sriyudthsak, Assoc. Prof., Faculty of Engineering, Chulalongkorn University
    Tayard Desudchit, Asst. Prof., Faculty of Medicine, Chulalongkorn University

    In this paper, we propose a novel approach to respiratory rate measurement using resonance tube to enhance the performance of microphone inserted and fixed at the end of the tube in catching breath sound signal from the mouth and/or nose. The signal is amplified and passed into envelope detector circuit after with it is compared with a suitable reference voltage in the comparator circuit to generate a pulse train of square wave synchronized with the respiratory cycle. A simple algorithm is developed in a small microcontroller (PIC16F628A) to detect rising edges of each consecutive square wave to calculate respiratory rate and display it on LCD together with analysis of breathing status. In order to evade noises which will cause errors and artifacts in the measuring system, the reference voltage is creatively designed to intelligently adapt itself to be low during expiration period and to be high during inspiration and pause period using the concept of resolving contradiction in the theory of inventive problem solving (TRIZ). This makes the developed device simple and low-cost with no need for complicated filtering system. It can detect breath sound as far as 250 cm from the nose and can perform accurately and more responsively with wide range of speed and level of breathing as tested against End Tidal CO2 Capnography device. The result shows the developed device can estimate precisely from as low as 0 BrPM to as high as 98 BrPM and it can detect shallow breathing as low as 10 mV of breath sound which we believe that it has high potentials for detecting hypopnea besides apnea event.

  • Perceived Service Quality and Commuter Segmentation of Informal Public Transport Service in Bangkok, Thailand (Accepted: 2019-07-13)
    Chutaporn Amrapala, Chulalongkorn University
    Kasem Choocharukul, Chulalongkorn University

    One informal public transport service in Bangkok is Silor (SR), given the meaning in Thai as four-wheeler. SR facilitates urban mobility both in terms of major travel mode and feeder to bus and mass transit lines in the city. This research aims to explore user subgroups characterized by attitudes through an Exploratory Factor Analysis followed by commuter segmentation through Cluster Analysis based on the obtained latent variables in order to propose future implications for SR service improvement in Bangkok. Interviews are conducted through questionnaire survey to collect users’ socioeconomic and trip profiles and attitudes towards SR service. The result reveals dimensions of service quality, which explain user perception and priorities regarding the service. Four segments of SR users are identified by four attitudinal factors, including reliability, invehicle environment, comfort and convenience, and environmental impact. Personal profiles, trip characteristics, and attitudes of each segment are analyzed and compared. Research findings would contribute to new knowledge on quality factors and area of SR service improvement as well as provide better understanding on diverse perception among SR user segments. Policy implications that best suit for each user segments are discussed.

  • The The Strategy of Visual Inspection for Non-Geometric Parts by using Screen Display Techniques (Accepted: 2019-10-07)
    phonsak lerthiranphanya, Department of Production Technology Education, Faculty of Industrial Education and Technology, King Mongkut’s University of Technology Thonburi, 126 Pracha Uthit Rd., Bang Mod, Thung Khru, Bangkok 10140, Thailand (Tel +66 870057676)

    The objective of this research is to determine the effectiveness of visual inspection strategies with different screen display techniques for non-geometric parts in terms of inspector performance measures to identify an effective strategy for inspecting non-geometric parts. The study is divided into three experimental phases. Phase I and Phase II compare the effectiveness of defect search patterns and training patterns respectively, to determine the best effective patterns. The results of both studies were integrated into screen display techniques to determine the most effective visual inspection strategy by using a visual inspection program in the final phase. Phase III compares the effectiveness of visual inspection with the strategy of screen display technique application. The evaluation of the effectiveness of all phases in regard to the performance of participants was indicated by speed and accuracy of the visual inspection. The results of the studies found that the visual inspection strategy with a hybrid screen display technique was the best strategy for visual inspection. This strategy will make visual inspection performance 13.40 sec faster per piece and increase accuracy by 50.83%. The application of the visual inspection strategy can be a strategy for practice before performing actual inspections and can have applications for other inspection work, especially for defect inspection of non-geometric shapes and complex shapes.

  • Quantification of different sources of over-strength in seismic design of a reinforced concrete tall building (Accepted: 2019-09-11)
    Kimleng Khy, Department of Civil Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, Thailand
    Chatpan Chintanapakdee, Center of Excellence in Earthquake Engineering and Vibration, Faculty of Engineering, Chulalongkorn University, Bangkok, Thailand

    An over-strength factor in seismic design plays an important role in computing actual forces in a structural member designed to remain elastic. However, sources contributing to this over-strength have not yet been systematically quantified for tall buildings. This paper aims to investigate the contribution from different sources of the over-strength factor in a reinforced concrete (RC) tall building. The contribution of slab-column gravity load framing to the lateral load capacity of the building is also investigated. A 39-story RC tall building subjected to earthquake ground motions in Bangkok was first designed according to the current building codes. Then, pushover analysis was conducted to compute the capacity curves of the building with three different specified strengths: design strength (with f factor), nominal strength (without f factor), and actual strength (with material over-strength). It was found that slab-column framing action contributes about 60% of the total lateral load capacity of the building.  The building has an overall lateral over-strength factor of 3.36 to 3.71. The over-strength factor arising from the design is 2.12 to 2.42 in which the contributions from strength reduction factor, material over-strength, and other sources involving the design requirements are about 1.10, 1.17, and 1.77, respectively. The over-strength factor arising from the redundancy due to the redistribution of internal forces is about 1.55 and the contribution from the steel strain hardening to the over-strength factor is relatively small.

  • Material Cost Prediction for Jewelry Production using Deep Learning Technique (Accepted: 2019-07-24)
    chanida phitthayanon, 0829565991
    Vichai Rungreunganun, King Mongkut's University of Technology North Bangkok

    Production cost management is a key factor to increase industrial competitiveness. The precious metal and the gemstone comprise 65% of the jewelry production cost. Managing raw material cost is a challenging task especially when the price highly fluctuates. In this article, deep learning models were developed to predict the prices of main raw materials of jewelry which are silver, gold, and diamond. These models are designed for Thai jewelry manufactures which are mostly small businesses. Therefore, our models only consider historical price data. This is because small businesses usually do not have access to other relevant data, i.e. oil prices and other economic data. The machine learning based models include in this work are a naive method, linear models, decision tree models, and deep learning models. The proposed precious metal price model can provide prediction RMSE of 0.765% which is comparable to other models in literature while requires less data and offers a simpler model. In addition, the proposed diamond price model can provide RMSE of 1.81% which is 53.2% more accurate than a naive method that normally used by jewelry manufacturers.

  • A New Landscape Classification Approach for Quantifying Spatial Pattern of Bac Kan Province, Vietnam (Accepted: 2019-08-08)
    Trong Dai Ly, Suranaree University of Technology
    Suwit Ongsomwang, Suranaree University of Technology

    Landscape theory and its application have played an important role in natural resources exploitation and environmental protection. Various classification approaches had been employed worldwide in landscape ecology studies. This paper had developed a new hierarchical landscape classification framework for quantifying spatial pattern of Bac Kan province. A landscape formation equation was applied with three natural factors (geology, topography, and soil) and cultural factor (land use). A multi-level segmentation technique with multiresolution segmentation algorithm was chosen to segment landscape units (patches) and to categorize landscape types at different levels. The results revealed that the landscape classification of Bac Kan province has 4 hierarchical levels. Level 4, which provided full details of spatial pattern based on geologic period, elevation, soil depth, and land use, had 315 landscape types. At this level, there are 8,427 landscape units mapped with a minimum and maximum areas of 0.02 km2 and 116.63 km2, respectively. A new Bac Kan landscape map at a scale of 1:100,000 along with 16 different attributes for each landscape unit was also produced. In conclusion, the framework of research methodology presented in this paper can be used as a guideline for landscape classification at provincial and national levels.

  • Forecasting Annual Solar PV Capacity Installation in Thailand Residential Sector: A User Segmentation Approach (Accepted: 2019-09-30)
    Muhammad Fachrizal, Sirindhorn International Institute of Technology, Thammasat University
    Jing Tang, Chulalongkorn University

    Solar PV is one of the fast-growing renewable energy in Thailand. Three sectors are contributing to solar PV installation, which are solar farms, industrial, and residential sector. However, the latter only contributes 1.39% of the cumulative capacity in 2016. By considering the lowering price of installation cost, growing affordable households, and a vast amount of solar irradiation in Thailand, it is of interest to observe the potential of the residential sector. Besides, there is a lack of study that focuses on the forecasting of residential solar PV in Thailand. Thus, this paper emphasizes on annual installation forecast of solar PV capacity in Thailand residential sector by using segmentation. This research categorizes residents into four categories, PV users with and without batteries, potential users, and rejecters, aimed to understand different types of users. An online survey of Thai residents about solar PV utilization was conducted from December 2017 to February 2018 to collect the data for the research. The results find that there is an exponential trend of increasing residential solar PV installation, followed by the reduction of payback period over time. It is forecasted about 3,511.4 MW of residential PV installation in the end of forecasting period. This research helps the decision maker to update the policies.

  • Numerical Simulation of Currents and Volume Transport in the Malacca Strait and Part of South China Sea (Accepted: 2019-10-25)
    Yudi Haditiar, Graduate School of Mathematics and Applied Sciences, Universitas Syiah Kuala, Banda Aceh 23111, Indonesia
    Mutiara R. Putri, Department of Oceanography, Bandung Institute of Technology, Bandung 40132, Indonesia
    Nazli Ismail, Department of Physics, Universitas Syiah Kuala, Banda Aceh 23111, Indonesia
    Zainal A. Muchlisin, 1 Graduate School of Mathematics and Applied Sciences, Universitas Syiah Kuala, Banda Aceh 23111, Indonesia; 2 Department of Aquaculture, Faculty of Marine and Fisheries, Universitas Syiah Kuala, Banda Aceh 23111, Indonesia
    Syamsul Rizal, Department of Marine Sciences, Faculty of Marine and Fisheries, Universitas Syiah Kuala, Banda Aceh, 23111, Indonesia

    The aim of this work is to determine the hydrodynamics of the Malacca Strait (MS) and the southern part of the South China Sea (SCS). The study uses the two-dimensional numerical model with a finite-difference method. The results show that the sea levels in MS and part of SCS are reversed and consistent with assimilation data that derived from Simple Ocean Data Assimilation (SODA). Sea level in northern MS is lower than that in the southern part during January and July. However, the interval of sea level elevation in both January and July appears differently. It is steeper in January than in July. Therefore, the currents and transports during January are stronger than those during July. However, in general, the direction of currents and volume transport of MS flow to the Andaman Sea both in January and July. In SCS, the pattern is relatively the same as in MS; that is, the currents during January are stronger than those during July.

  • Analysis of Tensile Strength and Optimization of Hot Air Welding Parameters on PVC-Acrylic Coated Polyester Fabric by Taguchi and ANOVA Technique (Accepted: 2019-10-10)
    Kunthakorn Khaothong, assistant professor

    There are several factors affecting the strength of welding seam through hot air for PVC-acrylic coated polyester fabrics. To obtain the most durability of the welding seam for practical use, the experimental design of this study adopts Taguchi method for determining a number of experiments. Each input parameter has 5 different levels. The result shows that the input parameters providing maximum tensile strength for welding in warp and weft directions are the following: the distance between a head of blower and workpiece (Dis) of 10 mm, the temperature of hot air (Tem) of 160 oC, the torque (Tq) of 9,000, and the speed of hot air (Sha) of 4,000 mm/s. The maximum tensile strengths are 95.38 kN/m and 86.17 kN/m for warp direction and weft direction, respectively. After filtering the input parameters at the significance level of 0.05, the input parameters which significantly affect the strength of welding seam are the distance between a head of blower and workpiece, and the temperature of hot air. Additionally, the relationship between the input parameters and the strength of welding seams can be established. The comparison between the actual experimental data and the predicted values of the tensile strength for both welding directions shows that the average percentage error is less than 0.1% so that the forecast equation is appropriate for the explanation of the variables for this study and provide statistical reliability.  

  • Pre-project Planning Process Study of Green Building Construction Projects in Thailand (Accepted: 2019-08-26)
    Kritsada Khun-anod, Kasetsart University
    Charinee Limsawasd, Kasetsart University

    Project effectiveness is a challenge in sustainable building construction projects. Lack of experience, knowledge, and skills in sustainable projects have been highlighted as the main barriers to using sophisticated and innovative techniques. Based on the literature, the pre-project planning effort directly influences a project’s success. Nevertheless, the differences in planning efforts for green projects have not been fully determined, especially in Thailand where sustainability just has been only recently considered in this context. This study investigated the status of pre-project planning for green building construction projects located in Thailand to promote sustainable construction. The analyses were performed based on two main objectives: (1) to compare the overall planning effort and (2) to address dissimilar planning factors between green and conventional projects. The concept of a project definition rating index (PDRI) was applied to evaluate the level of pre-project planning effort in 40 sample projects. An independent t-test was used for data analysis. The findings from this study indicated the importance of pre-project planning for green building construction that contributes all stakeholders to understand which aspects were differently implemented during the planning process in green compared to conventional programs.

  • Hotspot Location Identification Using Accident Data, Traffic and Geometric Characteristics (Accepted: 2019-08-26)
    Gholamali Shafabakhsh, Professor, Faculty of Civil Engineering, Semnan University, Semnan, I.R. of Iran
    yousef sajed, Ph.D. condidate, 1Faculty of Civil Engineering, Semnan University, University, Semnan, Iran
    yousef sajed, Ph.D. condidate, 1Faculty of Civil Engineering, Semnan University, University, Semnan, Iran
    morteza bagheri, Asistant Professor, Faculty of Railway Engineering, Iran University of Science and Technology (IUST).

    Determining the criterion for critical limits is always one of the essential challenges for traffic safety authorities. The purpose of identifying accident hotspots is to achieve high-priority locations in order to effectively allocate the safety budgets as well as to promote more efficient and faster safety at the road network level. In recent years, human, vehicle, road and environment have been recognized as the three main effective elements of the road transportation in the occurrence of accidents. In the present study, with combining the parameters related to accidents, geometric parameters of the accident location and traffic parameters, hotspots were identified by using the superior methods of Poisson regression and negative binomial distribution and based on the combined criteria of frequency and severity of accidents and equivalent damage factors. Then using Time Series Models in ANN, result were compared and validated. The results of ANN models demonstrate that the frequency method of accidents tends toward places with high traffic volume. MATLAB and STATA software were used. Non-native plumbing, curvature, slope, section length and residential area had more significance, and their coefficients indicated the significant effect of these parameters on the occurrence of the frequency and severity of accidents in hotspot locations.

  • Finite Element Modelling of Concrete-Encased Steel Columns Subjected to Eccentric Loadings. (Accepted: 2019-09-30)
    Akhrawat Lenwari, Chulalongkorn University
    Worakarn Anuntasena,

    This paper presents the 3D finite element (FE) analysis of concrete-encased steel (CES) short columns subjected to concentric or eccentric loadings. A new simplified technique of FE modelling that incorporates the concrete confinement behavior of the composite columns is proposed.This technique eliminates the need of predefined zones and constitutive properties of confined concrete.After validated with past experimental data, the FE analysis is used to construct the strength interaction diagrams and numerically investigate the effects of material properties including the compressive strength of concrete and yield strength of structural steel on the strength interaction diagrams of CES columns and assess the applicability of the plastic stress distribution method specified in AISC360-16 “Specification for Structural Steel Buildings”.

  • Seismic Shear Strengthening of Reinforced Concrete Short Columns using Ferrocement with Expanded Metal (Accepted: 2019-08-22)
    Dr. Phaiboon Panyakapo, Sripatum University, Thailand

    Typical reinforced concrete short column is brittle in shear rather than flexure under lateral cyclic loading due to its shear deficiency.  This paper presents the improvement of seismic behaviour of the reinforced concrete short columns which were strengthened by using ferrocement with expanded metal.  Full scale experiments were conducted for two strengthened concrete columns with different volume fractions of expanded metal and the control specimen under lateral cyclic loading.  It was found that the seismic behaviour in terms of the shear strength, stiffness, displacement ductility, and energy dissipation were significantly improved.  The expanded metal mesh with the high specific surface provided the better performance for controlling the crack propagation.  The brittle shear failure mode of the stirrup was reduced and the ductile flexure mode of the longitudinal reinforcement was dominant.  The reduced shear force of the stirrup was compensated by the shear force of the expanded metal reinforcement which experienced relatively large strain.  The technique of steel angle installation at the corners of column can successfully prevent the effect of sharpened corner wrapping of the mesh.  A model to predict the shear strength of the strengthened column is presented in term of the global efficiency factor for expanded mental.     

  • Geographically Weighted Regression Analysis Applied to the Establishment of Paddy Field Flooding Loss Functions (Accepted: 2019-06-10)
    Ling-Fang Chang, Agricultural Engineering Research Center Taoyuan, Taiwan
    Ming-Daw Su, National Taiwan University
    Wen-Tsun Fang, Agricultural Engineering Research Center Taoyuan, Taiwan
    Hsueh-Yen Shih, Agricultural Engineering Research Center Taoyuan, Taiwan

    Disasters due to typhoons and heavy rainfall occur frequently in Taiwan. With the increase of social and economic development density, flood damages are becoming more and more serious. Flood risk management has thus turned into a very important task. Flood damage assessment is the basis of flood risk management. The disaster damage estimation model is often divided into residential areas, industrial and commercial areas, agricultural areas and public facilities. Previous studies have mostly focused on residential, industrial and commercial areas. Agricultural losses are due to a large number of impact factors, and the relevant literature is insufficient. The most common methods are the loss curves for unit area and the flood depth loss curves method. Although the loss curves for unit area method is relatively simple, the differences in loss caused by various flooding depths are not considered. The flooding depth loss curve method often needs to be established through questionnaires. However, questionnaire surveys have to consume lots of manpower and material resources. Both the two methods above do not take the growth period of crops into consideration. When disasters occur in different growth periods of crops, the losses caused by the same flooding depth are different due to the various flooding tolerances of crops in each growth period. Due to the hydrological and geographical factors, such as climate, the growth period of rice transplanting is different due to dissimilar climatic conditions. The complexity of establishing a flooding loss curve for paddy field is thus obvious. In addition, in case the analysis of the flooding loss data is based on the traditional global regression analysis approach, there usually exists a spatial autocorrelation of the residual term with no consideration of spatial variation. This result violates the assumption of linear regression. In view of this, this study is expected to use paddy field as the research object. At first, paddy field loss factors considered in each literature are reviewed and studied. Relevant domestic factors are also collected and it then to establish a paddy field flooding loss estimation model, and then use the geographically weighted regression model for spatial analysis and spatial grouping comparison. The selection of the research site is to consider large-scale historical disaster events. The event is selected for analysis and assessment of the disaster area o of Typhoon Morakot in Kaohsiung City in 2008.

  • Flooding in Oda River Basin during Torrential Rainfall Event in July 2018 (Accepted: 2019-06-10)
    Shakti P. C., National Research Institute for Earth Science and Disaster Resilience (NIED), Tsukuba, Japan
    Hideyuki Kamimera, National Research Institute for Earth Science and Disaster Resilience (NIED), Tsukuba, Japan

    Extreme rainfall events cause severe flooding and/or landslides almost every summer in Japan. It seems that the frequency of such events and induced human/economic losses has increased in recent years. A torrential rainfall event in early July 2018 caused severe flooding in many river basins over Hiroshima and Okayama Prefectures of western Japan and resulted a number of fatalities and serious damage to property. One of them is the Oda river basin (about 498 km2), which was severely affected by the flood during the event. Different types of observation systems were used to measure or estimate rainfall for this event. Comparison of radar and satellite-based rainfall shows a good agreement with the rain gauge observations of the entire period. Basin-mean total rainfall from Japan Meteorological Agency’s analyzed radar rainfall (RADJ), Water and Disaster Management Bureau’s radar rainfall (RADW), Automated Meteorological Data Acquisition System (AMeDAS), and satellite-based rainfall data (GSMaP) were about 314, 322, 357 and 304 mm during July 5–7 2018. In this study, we applied Rainfall–Runoff–Inundation (RRI) to acquire a detailed understanding of flood processes in the Oda river basin. All the available rainfall data including different spatial resolution of hydrographic features were considered as the main input data in the model separately. Gridded flow and map of the possible maximum flood depth across the basins were generated and validated. Simulated results based on high resolution topographic data are more closely aligned with observed data. It is also found that the maximum flood inundation areas estimated by the RRI model using radar rainfall data appeared somewhat closer with the extent of flood-affected areas from the model with data of the Japanese Geospatial Information Authority (GSI) over the Mabi city. It is believed that modelled results can be used an important reference in the disaster mitigation and that they may be useful for further studies.

  • Estimation of Groundwater Use Pattern and Distribution in the Coastal Mekong Delta, Vietnam via Socio-Economical Survey and Groundwater Modelling (Accepted: 2019-06-10)
    Tuan Pham Van, Chulalongkorn University
    Sucharit Koontanakulvong, Chulalongkorn University

    In many provinces of Mekong delta, excessive groundwater extraction has resulted in many serious groundwater-related problems. To solve problems relevant to increasing water demand as well as other negative influence of groundwater depletion, an exigent question was raised whether at what time in future is the limits to local groundwater use reached? Hence, there is a need to know groundwater use (GWU) pattern and distribution in the study area for future groundwater management. In this study, firstly, the study used socio-economic data of Tra Vinh Province to classify groups of revenue, potential of water resources and population distributed in each district in order to design and conduct the socio-economic survey and to explore information relevant to GWU for each purpose. Secondly, the data set of 419 survey questionnaires per 9 surveyed communes were analysed by SPSS tool to estimate ratio of household using groundwater (RHHUG) for each purpose as well as average pumping rate (APR) per household for domestic use and per ha for agriculture use, respectively. Thirdly, the APRs were extended to propose the total GWU pattern and distribution during 2007-2016 by using socio-economic data of the province and expand to spatial distribution by using correlation with land surface temperature (LST) which was estimated from Landsat 8 images. Besides, the groundwater flow model of the study area was developed to verify the estimated amount of groundwater pumping (pattern and distribution) in the period. The study found that the annual GWU of Tra Vinh Province in 2016 was 347,793 m3/d in which two coastal districts occupied more than 50 percentages, i.e., about 188,551 m3/d. RHHUG increased from 2 to 3 times during the period of 2007 to 2016 in this area. LST distribution performed a good correlation (adj-R2 = 0.646) with GWU distribution in Tra Cu district. Results of groundwater modelling also showed that the discharge from aquifer (mainly pumping) was always higher than the recharge to aquifer.

  • A Study on Local Knowledge in Adaptation to Landslide Disasters in Sri Lanka (Accepted: 2019-06-10)
    Uditha Akalanka Dasanayaka, Nagaoka University of Technology
    Yoko Matsuda, Nagaoka University of Technology

    Natural disasters are unforeseen events which occur at hydrologic, geologic, and atmospheric origins. The Policy-makers still rely on mitigation strategies based on scientific approaches. However, many scholars had emphasized the importance of incorporating local knowledge and related practices for disaster risk management. In that context, this study investigates the local knowledge in adaptation to mitigate the landslides disaster situations by studying a village in Sri Lanka which is located at the central region of Sri Lanka which is vulnerable for landslide disasters. Landslides is one of the severe types of disasters in hilly terrains and which cause to loss of lives and property damages especially in Asia region. This study employed the field surveys, questionnaire surveys and semi structured interviews for data collection. The findings of the research indicate how the local knowledge-based practices in settlement layout & planning, landscaping had enhanced disaster adaptation level of the community. Further the local knowledge-based value systems act as a strong mechanism in identifying early signs of landslide disasters. Finally, the paper discusses the possibilities of upscaling such local practices for mainstream disaster management practices.

  • Fe and Co-doped (Ba, Ca)TiO3 Perovskite as Potential Electrocatalysts for Glutamate Sensing (Accepted: 2019-09-30)
    Nicha Sato, Kasetsart University
    Makito Haruta,
    Kiyotaka Sasagawa,
    Jun Ohta,
    Oratai Jongprateep,

    Barium titanate (BaTiO3) and calcium titanate (CaTiO3) are renown perovskite-structured dielectric materials. Nevertheless, utilization of BaTiO3 and CaTiO3 in sensing applications has not been extensive. This study, therefore, aims at examining potential usage of BaTiO3 and CaTiO3 as enzyme-less sensors.  BaTiO3, CaTiO3, Fe-doped BaTiO3, Co-doped BaTiO3, Fe-doped BaTiO3, and Co-doped CaTiO3 (with Fe and Co 5 at%) were synthesized by solution combustion technique, compositionally and microstructurally examined, and tested for their electrocatalytic activities. All powders consisted of submicrometer-sized particles. Measurements of electrocatalytic activities in 0.01 M glutamate solution by cyclic voltammetry were performed. It was found that oxidation peaks occurred at applied voltage close to 0.6 V. Peak currents, which denoted electrocatalytic performance, were prominent in doped powders. Electrocatalytic activities of the powders were discussed with respect to chemical composition, microstructure, and electronic characteristic of the materials.

  • Logistic Regression Analysis of Factors Affecting Travel Mode Choice for Disaster Evacuation. (Accepted: 2019-10-28)
    Thanawan Phiophuead, Dept. of Civil Engineering, Kasetsart University, Kamphaeng Saen, Nakorn Pathom, Thailand

    The purpose of this research was to analyze the relationships among the factors affecting the travel mode choice between government vehicles and private vehicles used for the evacuation of people in areas experiencing floods and landslides. The relationships were developed using a utility function to predict the probability and proportion for selection of travel mode in future evacuations based on binary logistic regression. Three models were developed using different analytical factors based on survey data of the sample group of people in Mae Pong watershed, Laplae district, Uttaradit province. It was found that the factors affecting the selection of travel modes in all three models consisted of sex, families with young members, education, vehicle ownership, experienced a disaster, recognition of shelter location, safe, fast, comfortable, privacy, easy for evacuation, and difference between travel time and walking time to the assembly point. Models 1, 2, and 3 could predict with accuracies of 79.86, 73.46, and 73.86 percent respectively.

  • Experimental Characterization of Maize Cob and Stalk Based Pellets for Energy Use (Accepted: 2019-09-30)
    M. A. Sulaiman, Olabisi Onabanjo University
    Babatunde Olusola Adetifa, Olabisi Onabanjo University
    S. O. Adekomaya, Olabisi Onabanjo University
    N. S. Lawal, Olabisi Onabanjo University
    O. O. Adama, Olabisi Onabanjo University

    The quest for alternative energy sources is gradually shifting from natural fossil fuel to alternative bio-resources especially agricultural waste products due to their reduced pollution risk and sustainability. This study seeks to investigate the suitability of plant residue pellets to produce biomass. The plant residues investigated include corn cob and corn stalk. Three samples produced include 100% granulated corn cob residues, 100% granulated stalks and a composite of 50:50% granulated corn cobs and stalk residues. The mixed residues were pelletized using cassava starch as a binder. The pellets were experimentally analyzed using ultimate, proximate and calorimetry analyses. Among three sets of maize residue pellets investigated, the result of the cob-stalk 50:50% combination show that it has 0.64% nitrogen, 48.57% carbon, 0.38% Sulphur, 6.22% hydrogen, 55.81% oxygen, 3.25% moisture content, 2.20% ash content, 80.0% volatile matter, 17.80% fixed carbon percentage, HHV of 32.9 kJ/kg, an average CO2 value of 563±50 PPM, an average CO value of 100±50 PPM, an average value of 69±4% relative humidity and an average temperature of 27.5±0.5%. The study reiterates that corn stalk is a good bio-fuel and should be encouraged to address the current energy shortfalls in the country.

  • Transformation Optical User-Friendly Interface for Designing Metamaterials (Accepted: 2019-09-12)
    Wanchai Pijitrojana,
    Pasit Jarutatsanangkoon, Thammasat University

    Transformation optics offers a procedure to design the structures of metamaterials to find the material parameters needed in various applications. However, a methodology of a transformation optics is too complicated. To help users who are beginning to study metamaterials and transformation optics, a transformation optical user-friendly interface is developed. The interface is implemented based on the free-form touch transformation. By combining various transformation templates, a fully arbitrary transformation can be realized. Transformation templates are created by basic functions. The interface provides both the input method as well as the real-time visualization of the space. The program uses model-view-controller architecture. Three examples from the touch interface are verified by the FDFD simulation.

  • Evaluation and Prediction of the Scour Depth of Bridge Foundations with HEC-RAS Numerical Model and Empirical Equations (Case Study: Bridge of Simineh Rood Miandoab, Iran) (Accepted: 2019-09-30)
    Rasoul Daneshfaraz, Associate Professor, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, East Azerbaijan, Iran

    Today, scouring is one of the major issues in the river and coastal engineering. Each year, many bridges around the world are destroyed due to neglecting hydraulic elements. In the present study, scour depth around the piers of the Simineh Rood Bridge in Miandouab, Iran were investigated using empirical relationships and the HEC-RAS numerical model, and the results are compared with each other. Firstly, a hydraulic software model was created from the river where the bridge was located using field data. Then, by entering the scouring data of bridge piers for discharges with a return period of 5 to 1000 years, changes in flow discharge were investigated for scouring around the middle and lateral sides of the bridge. Results of the empirical equations showed that some of the equations are not sensitive to increases in flow discharge, and for each return period, the results are near each other. Also, numerical model results showed that with an increase in discharge, scouring increases in the bridge’s middle and lateral piers. In all discharges, the first and the seventh pier had the lowest and highest scour depth, respectively. Also, the left and right abutments are heavily influenced by increasing discharge. In discharges with a return period of 1000 years, the scour depth was 11.19 and 6.32 m. The Frohlich method is not as sensitive as the CSU method to an increase in discharge when calculating scour depth. Finally, the results of the numerical model were compared with experimental empirical equations

  • Applications, Manufacturing and Thermal Characteristics of Microlattice structures: Current State of the art (Accepted: 2019-10-28)
    Anirban Sur, Symbiosis Institute of Technology, Symbiosis International (Deemed University), Pune, India

    Micro-lattice structures are emerging as multi-functional devices. They possess excellent heat transfer capabilities, energy absorption abilities, vibration control abilities, etc. The higher surface area to volume ratio of micro-lattice structures makes them suitable for heat transfer applications where compact and lightweight heat transfer mechanism is necessary such as in case of space and transportation. The heat transfer and mechanical load-bearing properties of micro-lattice structures can be tailored by altering several parameters such as the lattice strut angle, node-to-node spacing, the diameter of the strut, etc. In this paper, micro-lattice structures, their manufacturing methods, applications are reviewed and a passive heat transfer mechanism consisting of micro-lattice heat pipe is proposed for the battery thermal management system in electric vehicles.

  • PDMS Material Models for Anti-fouling Surfaces Using Finite Element Method (Accepted: 2019-10-25)
    Kotchakorn Thanakhun, 111/754 Moo 3 Thareang Bangkhen Bangkok

    Ecofriendly anti-fouling surfaces are usually produced by lithographic techniques which will fabricate micropillar-like surfaces made of low surface energy materials such as Polydimethylsiloxane (PDMS). The purposes of this research were to investigate the most suitable Polydimethylsiloxane (PDMS) material model available in ANSYS APDL program to simulate structural behaviors of micropillars subjected to shear loading and to develop micropillar with improved lateral strength. In this research, PDMS material models were derived from experimental data from uniaxial tensile test. The accuracies of the PDMS material models, which were the Neo-Hookean, Mooney-Rivlin 3 and 5 parameters, Ogden (1, 2, 3 terms), Yeoh (1st, 2nd, 3rd order) and Arruda-Boyce material models, were evaluated and compared to experimental data from uniaxial tensile test and punch-shear test. Moreover, micropillars made of a pure PDMS and a Polyurethane Acrylate (PUA) core coated with PDMS were studied to compare their lateral strength under shear loading. We found that the most accurate material model to simulate both the uniaxial tension and shear loading was the Yeoh 3rd order material model; however, these accuracies would valid for small strain range. The lateral strength of a micropillar made of PUA core coated with PDMS was 8.67-time of the one made of pure PDMS. The thickness of the coated material was not a significant effect on lateral strength of the micropillar.

  • Evaluation of Economic Damages on Rice Production under Extreme Climate and Agricultural Insurance for Adaptation Measures in Northeast Thailand (Accepted: 2019-07-25)
    Koshi Yoshida, Ibaraki University
    Mallika Srisutham, Khon Kaen University
    Supranee Sritumboon, Land Development Department, Thailand
    Desell Suanburi, Kasetsart University
    Naruekamon Janjirauttikul, Land Development Department, Thailand
    Weerakaset Suanpaga, Kasetsart University

    In northeast Thailand, the irrigated agricultural land was only 7.6% (in 2012) of total and others were classified as rain-fed so that climate change makes agricultural production unstable and also makes negative impact to the societies and economics in rural area. To mitigate these issues, it is desirable to develop enhanced adaptation measures. In this study, we focused on weather induced economic damages and effectiveness of index-based insurance system in Northeast Thailand. Firstly, we evaluated how affect the seasonal rainfall amount and patterns on rice yield and production through regression analysis by using the meteorological and agricultural statistic data. 8 province had positive correlation R>0.3 with Jul-Sep accumulated rainfall. And then, probability analysis was applied to monthly rainfall which was employed for insurance index value. As a result, setting amount and periods of insurance index was suitable. Secondly, household survey was conducted to investigate farmer’s conditions of water use, cultivation, income balance. In recent year, agricultural damage on farmer’s income was not so large (less than 3%), because 65% of farmers income relied on non-agricultural sector. That might be the one reason of constraints of insurance sales.

  • Characteristics of Gridded Rainfall Data for Thailand from 1981–2017 (Accepted: 2019-07-25)
    Shojun Arai, Toyama Prefectural University
    Kazuya Urayama, Toyama Prefectural University
    Taichi Tebakari, Toyama Prefectural University
    Boonlert Archvarahuprok, Thai Meteorological Department, Thailand

    We used a spatially interpolated gridded dataset produced by the Thai Meteorological Department (TMD) to explore long-term rainfall trends. We placed data from 1981–2017 into a 0.5° grid using the Kriging method. Long-term trends in maximum daily and monthly rainfall, and total annual rainfall, were analyzed using the nonparametric Mann–Kendall trend test. Chumphon, Lamphun, Nakhon, Sawan, and Buriram provinces exhibited significant positive trends in the annual maximum daily rainfall (p<0.05, p<0.01). The coastal area of Chachoengsao Province exhibited a significant negative trend (p<0.05). January rainfall showed a negative trend throughout Thailand. Annual rainfall showed a positive trend in many regions, especially in northern, northeastern, and southern areas. The eastern region exhibited a negative trend but statistical significance was not attained. The 10-, 30-, 50-, and 100-year daily rainfall probabilities were estimated using the Generalized Extreme Value method. The eastern side of the southern region exhibited remarkably high rainfall.

  • Prospect of Discharge at Daecheong and Yongdam Dam Watershed under Future Greenhouse Gas Scenarios using SWAT Model (Accepted: 2019-07-25)
    Seonhui Noh, Chungnam National University
    Mikyoung Choi, Chungnam National University
    Kwansue Jung, Chungnam National University
    Jinhyeog Park, K-water Institute of Water and Environment, Korea

    In this study, the future expected discharges is analyzed at Daecheong and Yongdam Dam Watershed under Future Greenhouse Gas Scenarios based on RCM with 1 km spatial resolutions from Korea Meteorological Agency(KMA). HadGEM2-AO, which is the climate change prediction model that KMA recently introduced is used for this study. Geum river watershed area is 9,914.013 km2 and there are two dams, one of dam is Daecheong Dam completed in 1980, the other dam is Yongdam Dam completed in 2001. The runoff is simulated using the ArcSWAT model from 1988 to 2010. The simulation is in good agreement with measured data at the Yongdam Dam and Daecheong Dam showing R2 of 92.25% and 95.40% respectively. Using the average discharge from 2001 to 2010 as a baseline, the simulated annual average discharge increased by approximately 47.76% and 36.52% under the RCP4.5 scenario and RCP8.5 scenario respectively for the from 2011 to 2100.

  • Load Feasible Region Determination by Using Adaptive Particle Swarm Optimization (Accepted: 2019-09-30)
    Patchrapa kiara Wongchai, Electrical Engineer

    The proposed of a method for determination a space of feasible boundary points, by using adaptive particle swarm optimization in order to solve the boundary region which represented by particle swarm points. This paper present method supports the calculation for a large-scale power system. In case of contingency will illustrate the point on the plane x-axis and y-axis dimensional power flow space. In addition, This method not only demonstrates the optimal particle swarm through the boundary tracing method of the feasible region but also present the boundary points are obtained by optimization. Moreover, receding loss function and operational constraints simultaneously are considering. The formulation points of feasible region can also determine the boundary points which is the contingencies are taken into account and the stability of load demand that system allows to execute in the normal requirements. These feasible points defined the limit of control actions and the robustness of operating points. Finally, the test systems shown the impact of system parameters on the load shedding, generator voltage control, and load level.

  • Using Artificial Neural Network for Selecting Type of Subcontractor Relationships in Construction Project (Accepted: 2019-11-19)
    Pisal Nov, Chulalongkorn University

    Since some subcontractors could perform their professional skills faster and less expensive, many main contractors have adapted those companies to help their construction works and gained more profits. After the relationship between main contractor and subcontractor was consistently developed by many construction projects, main contractors would be willing to define a potential subcontractor who could ensure a good productivity in the future. Previously, main contractors were experienced by wrong selection of subcontractor in relationship development. Thus, it could cause some controversies between main contractor and subcontractor and hinder benefits with a right subcontractor for a long run business. To minimize the problem of main contractor, this paper used an artificial neural network as a tool for determining the subcontractor in relationship development. As the result, the artificial neural network provided higher accuracy in training and validating data and it could give main contractor more confident in decision making for selecting type of subcontractor relationships.

  • Influence of Type and Compositions of SCMs on Expansion of Mortar Bars from Alkali Silica Reaction (Accepted: 2019-11-04)
    Chakkarphan Sangsuwan, Kasetsart University, 50 Pahoyothin Rd., Jatuchak, Bangkok 10900
    Suvimol Sujjavanich,

    The effect of different local pozzolans, as a supplementary cementitious material (SCM), on the expansion of mortar bar due to Alkali Silica Reaction (ASR) were reported in this paper. Accelerated test on specimens using local volcanic aggregates, rhyolite, was used to investigate and to compare the effects of fly ash (FA) and metakaolin (MK) on the suppression of the length change. In this study, three different percentages of FA, namely, 20, 35 and 50 and three of MK, namely, 10, 15 and 20 were used in cement replacement. The results showed the lowest expansions at 14 days were -0.036% and -0.001%, respectively for 35% FA and 10% MK, compared to 0.176 % of the control mix. Results from 28 days acceleration registered a slight increase in expansion for both FA and MK mixes.  Increase the SCMs to 50% FA and 15-20% MK yielded reduction of expansion to the innocuous level for both short and long term expansion. Chemical composition analysis revealed decrease in CaO/SiO2 and CaO/Al2O3 of the cementitious systems. This could affect the expansion reduction.  But alumina in Al2O3/SiO2 show the dominant effect on ASR suppression. Microstructures of all materials and casted specimens were also studied in detail. Considering all aspects, these SCMs were considered good candidates for ASR prevention in new concrete structures.

  • A Parametric Investigation of the Steam Injection Gas Turbine System on a Cogeneration Plant (Accepted: 2019-11-13)
    Chittin Tangthieng, Department of Mechanical Engineering, Chulalongkorn University

    The aim of this study is to conduct a parametric investigation of the steam injection gas turbine system by focusing on the effect of the steam mass flow rate on the energy transfer behaviors of a cogeneration plant.  A thermodynamic model of two gas turbine cycles and one steam turbine cycle and a heat transfer model of the heat recovery steam generator are developed.  A successive iteration is employed to solve a set of equations and obtain a converged solution.  The result shows that by increasing the mass flow rate for the steam injection gas turbine system from 0 to 2 kg/s, the input energy rate from the fuel and the total electrical output power from the cogeneration plant are increased, resulting in an increase of the cogeneration electrical efficiency from 49.9% to 50.4%.  On the other hand, the output heat rate from the steam from the cogeneration plant is decreased, resulting in a decrease of the cogeneration heat efficiency from 8.5% to 5.4%.  Consequently, the primary energy saving of the cogeneration plant decreases from 16.6% to 14.9%. 

  • Making Undergraduate Labs Challenging and Useful (Accepted: 2019-10-30)
    Gridsada Phanomchoeng, Mechanical Engineering Department, Chulalongkorn University, Bangkok 10330, Thailand

    Learning through laboratory work is critical in high quality science education. Traditional engineering labs are useful but not challenging. However, when the same labs are repeated every year, and students know the results, it is questionable how much is really learned. Students may copy the results from last year’s labs, making it difficult for instructors to evaluate their work. To address this problem, the Mechanical Engineering Experimentation and Laboratory II class was revised. A new lab designed to be challenging and useful by using a current research topic to guide it. The class taught in new class environment with state of the art facilities. Students learn instrumentation in a way that forces them to think about the problem, develop a method to measure a phenomenon, and draw conclusions about the results. The tangible connection to research motivates students. It takes professors more time to create these labs. However, since the results fold directly into their research objectives, i.e., gathering data needed for publications, the approach ultimately becomes an efficient use of time. It is fairly common for professors to ignore undergraduate labs, but this paper shows that with a little bit of effort, these labs can provide a significant learning experience for students. Based on the survey, more than 90% of students agree that the new lab help them to develop defining problem, designing experiment, analyzing, concluding, and reporting skills. More than 70% of students agree that they learn new measurement equipment for the new lab. Also, 91% of students would recommend other students to take the new lab. Moreover, this paper shows that the results from the lab lead to the manuscript which has submitted to a journal. 

  • Hardware Software Co-Design of a Farming Robot (Accepted: 2019-11-05)
    Gridsada Phanomchoeng, Mechanical Engineering Department, Chulalongkorn University, Bangkok 10330, Thailand

    Food means life and no one can think about living without food. This is the most fundamental human necessity and food security is one of the major global concern of this century. With the revolution and recent advancements in the field of electronics and communication, there has been a paradigm shift from conventional farming ways to the modern one. This paper talks about the development of hardware software co-design of agricultural farming robot. Our developed farming robot has two parts namely hardware part which further consists of mechanical, electrical, control and tools segments and the software part which allows user to interact with the farming robot via cloud service. Our proposed hardware architecture is compatible with commercial Farmbot product and the developed web-based software can be extended for more features and applications. Furthermore, the developed robot has been tested and it works well.

  • Blockchain Technology, Technical Challenges and Countermeasures for Illegal Data Insertion (Accepted: 2019-11-12)
    Soamsiri Chantaraskul, The Sirindhorm International Thai German Graduate School of Engineering, King Mongkut’s University of Technology North Bangkok
    Muhammad Aitsam, The Sirindhorm International Thai German Graduate School of Engineering, King Mongkut’s University of Technology North Bangkok

    Blockchain is a decentralized transaction and data management technology. It was developed for the world’s first cryptocurrency known as Bitcoin in 2008. The reason behind its popularity was its properties which provide pseudonymity, security, and data integrity without third-party intervention.  Initially, most of the researches were focused on the Bitcoin system and its limitation, but later other applications of Blockchain e.g. smart contracts and licensing [1] also got famous. Blockchain technology has the potential to change the way how transactions are conducted in daily life. It is not limited to cryptocurrencies but could be possibly applied in various environments where any forms of transactions are done. This article presents a comprehensive overview of Blockchain technology, its development, applications, security issues, and their countermeasures. In particular, the security towards illegal data insertion and the countermeasures is focused. Our analysis of countermeasures of illegal data insertion can be combined for increased efficiency. After the introduction of the Blockchain and consensus algorithm, some famous Blockchain applications and expected future of Blockchain are deliberated. Then, the technical challenges of Blockchain are discussed, in which the main focus here is on the security and the data insertion in Blockchain. The review of the possible countermeasures to overcome the security issues related to data insertion are elaborated.

  • Weighted-Probability Random Number Generator for PLC Channel Transfer Function Generation (Accepted: 2019-10-30)
    Lovelyn C. Garcia, De La Salle University
    Ann E. Dulay, De La Salle University
    Gicel Mari I. Oseña, De La Salle University

    The concept of randomization shows many realistic scenarios and has enormous applications in everyday life. However, existing random number generators have poor adaptability when representing some of the actual occurrences in natural environment, such as in biology, mobile communications, and even electrical behavior. For PLC channel transfer function generation, biased sampling of the channel is more applicable. This paper proposes a weighted-probability method to generate random numbers to emulate the real-world variations of a power line communications channel. Existing PLC channel emulator can mimic the random behavior of the channel, altered by several parameters such as cable length, cable type, presence of loads, and ejecting different noises. However, the scenario of integrating the effect of changing the state of the loads and channel variation due to time is not well represented in the normal random channel generation. The best concept for this scenario is the weighted random number generator (WRNG). This work developed an algorithm in Matlab and VHDL, implemented it in FPGA and integrated it with an existing PLC channel emulator. The emulator is implemented using Kintex-7 FPGA. In this study, ten different weights corresponding to the probability of occurrence of the actual household appliances and eighty transfer functions were used as inputs to the program. The randomness and periodicity of the WRNG are tested and passed the Runs test. Autocorrelation and histograms are used to determine the correct implementation of the weights.