• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.1
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• pp.10-15
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• 2003

This paper presents the digital computer performance evaluations of the three-phase self-excited induction generator (SEIG) driven by the variable speed prime mover such as the wind turbine using the nodal admittance approach steady-state frequency domain analysis with the experimental results. The three-phase SEIG setup is implemented for small-scale rural renewable energy utilizations. The experimental performance results give a good agreement with those ones obtained from the digital computer simulation. Furthermore, a feedback closed-loop voltage regulation of the three-phase SEIG as a power conditioner which is driven by a variable speed prime mover employing the static VAR compensator (SVC) circuit composed of the thyristor phase controlled reactor (TCR) and the thyristor switched capacitor(TSC) is designed and considered herein for the wind-turbine driven the power conditioner. To validate the effectiveness of the SVC-based voltage regulator of the terminal voltage of the three-phase SEIG, an inductive load parameter disturbances in stand-alone are applied and characterized in this paper. In the stand-alone power utilization system, the terminal voltage response and thyristor triggering angle response of the TCR are plotted graphically. The simulation and the experimental results prove the effectiveness and validity of the proposed SVC which is controlled by the Pl controller in terms of fast response and high performances of the three-phase SEIG driven directly by the rural renewable energy utilization like a variable-speed prime mover.

• Journal of the Korea Convergence Society
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• v.11 no.1
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• pp.169-174
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• 2020

Side bolster is a part of the vehicle seat that holds the passenger's body from the side to make it more stable when the passenger is seated in the seat. In this study, the structural and fatigue analyses of the side bolsters at a car seat were carried out with two models of A and B. The heavily loaded parts, the damage by fatigue at driving a car and the difference of durability due to the structure were examined and the distributions of stress and deformation, and the fatigue lives were seen. Also, the strength and durability were examined. This study result is thought to be devoted to decrease the fatigue damage and increase the fatigue life and durability according to the design of bolster. This result is able to improve the product by applying the design of automotive side bolster practically. And it is thought to be the advantage to apply this study result to the convergence research with esthetic sense.

• Korean Journal of Agricultural Science
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• v.44 no.2
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• pp.272-282
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• 2017

In Bangladesh, since the beginning of 21st century, the poultry industry has become an unparalleled platform for a quick profit, the generation of local employment, and the production of cheaper animal proteins. This paper summarizes poultry industry-related facts and figures for Bangladesh, starting from the very beginnings of this sector when poultry farming was part of subsistence family farming only to today's highly commercialized horizon, through personal experiences, secondary data analysis, spot visits, and the sharing of views and ideas with stakeholders. A critical analysis reveals that the poultry industry in Bangladesh may become multi-dimensional and more stable in the near future as it establishes sufficient backward and forward linkages to input and output supplies. We can foresee its passing the very fast growing juvenile stages of higher net profit earning and less responsible then becoming fully mature. The projected demand and production potentials of this sector are increasing, but at a slower pace than before, in the face of some important challenges like emerging disease, higher prices of inputs, consumer preferences, and strong market competition. However, evidence suggests that the production systems of poultry in Bangladesh are entering a new era to cater to the needs of consumers, society, and government as it produces healthier and more diversified, further-processed foods, in the coming years. A better economy in the country, a more health-conscious population, and the availability of new and affordable innovations in this sector might be the driving forces to support the foreseen transformations.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.5
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• pp.274-278
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• 2016

A road energy harvester was designed and fabricated to convert mechanical energy from the vehicle load to electrical energy. The road energy harvester is composed of 20 piezoelectric materials. This study attempted to evaluate output depending on pavement materials when paving road piezoelectric energy harvester in the road. Harvester is the bender type and is the method of supporting the both ends of piezoelectric material and applying the load in the middle part. Harvester was paved in the type paved with asphalt, type paved with cement and in the exposed type not covering the top of harvester. The output characteristics were compared and evaluated depending on changes in vehicle load and vehicle speed changes. As vehicles, truck (11.9 ton), SUV(1.6 ton) and sedan (1.5 ton) were used and the output characteristics when driving at the interval of 10 km/h from 10 km/h to 100 km/h were evaluated.

• The KIPS Transactions:PartD
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• v.12D no.1 s.97
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• pp.151-158
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• 2005

In order to use the existing map data base in the mobile phone, the dynamic creation technique of the radio map which will be able to be converted into the raster image and transmitted was proposed. We transferred the client module functions such as the coordinate conversion, data compression and decoding to server, and made driving of JAVA browser in the mobile phone which has the restricted resources possible for the dynamic creation of the radio map. We made the radio electronic map service possible without map data base for the mobile phone use only by performing the general work of the map at the sever. And we guaranteed the client waiting time less then the limit time by performing the filtering work of the map at the server also. After we input the keyword at the user interface for searching the region or facility, and verified the performance of the proposed technique by confirming that the raster electronic map usable at the mobile phone was created dynamically.

• The KIPS Transactions:PartC
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• v.9C no.4
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• pp.481-488
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• 2002

Guarantee of the data integrity is important to the Virtual Private Network (VPN) which can be improved cost decreasing and effective work by applying on Internet as the private network. Thus, the integrity function in the VPN must be maintained and the security manager must be check it occasionally. In this paper we propose the VPN Integrity Evaluation System (VIES) which is collecting, and evaluating automatically the vulnerable data of VPN against current hacking mechanisms in information security system. And this VIES obtain to the results which have objectivity and fairness of evaluation by driving off the evaluation scenario based on Common Criteria (CC), and general users or non-specialist can utilize easy the security evaluation of organization.

• Korean Journal of Construction Engineering and Management
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• v.2 no.3 s.7
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• pp.75-82
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• 2001

Traditional bidding process and activities in public construction area has many problems in terms of the clearness and fairness of administration. And, it causes many cost consumption to suppliers. As part of the efforts to solve these problems, some public institutions developed the electronic bidding systems. But these systems have still problems in diverse aspects. Therefore, the purpose of this study is to analyze current bidding systems through literature survey, case study and process mapping methodology, to compare the result of the analysis with the developed electronic bidding systems and to suggest the improvement for the coming bidding systems. As results of this study, key processes and classified contract types about public construction bidding were identified. These can be applied by means of guidelines when public institutions are planning new electronic bidding systems. The composition of unified driving organization, the database development for information share and the standardization of national level for the new electronic bidding systems were also suggested.

• Journal of the Korea Convergence Society
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• v.6 no.5
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• pp.85-90
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• 2015

In this study, the life evaluation due to the structural configuration of bumper attached at the front side of ATV vehicle is studied on the basis of fatigue analysis. As the purpose of this study, the characteristic of bumper exposed on the repetitive loading condition like the vibration is understood. The position of crack happened at the fatigue situation is grasped in advance and complemented in advance. It is considered that the multipurpose vehicle is designed to not be driven on the paved general road but the rough road like the unpaved load. And the weak part of bumper is understood through the study of life evaluation on this driving environment. The durability can be improved by doing the safe design of automotive bumper on the basis of the analysis result. And it is possible to be grafted onto the convergence technique at design and show the esthetic sense.

• Journal of Biosystems Engineering
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• v.30 no.3 s.110
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• pp.147-154
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• 2005

The improved hitch device, which connecting the trailer to power tiller, was developed. This device, composed with spring and rubber, could reduce the vibration and shock levels during driven on off-road. The vertical vibration accelerations for the improved hitch device were measured at 6 positions, i.e. engine, hitch, seat, and three points in trailer (front, middle, and rear) for not driving but at low engine speed of 500 rpm, and compared with the existing hitch device. The results of this study could be summarized as follows; The average vibration acceleration up to 120 Hz was $0.4m/s^2$ at engine part, but it was 0.08 and $0.05m/s^2$ at trailer for existing and improved hitch device, respectively. About $38\%$ of average acceleration level could be absorbed for the improved hitch device compared with existing hitch device. The average vibration acceleration up to 40 Hz was reduced to 0.12 and $0.06m/s^2$ at trailer for existing and improved hitch device respectively, showing the reduction effect of $50\%$. The maximum acceleration occurred at up to 20 Hz of low frequency was much higher than total acceleration occurred at up to 120 Hz, which means that much loss or damage could be occurred during transporting of agricultural products on off-road. The portions of average acceleration occurred at up to 20 Hz of low frequency were $27\%\;and\;21\%$ for the existing and improved hitch device, respectively.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.55-56
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• 2006

This paper describes a new concept of the robot that can climb on the vertical plane. The engineering design problem of the main structure is presented and the experimental results regarding a new mechanism of climbing on the vertical wall are discussed. The locomotive motion of the robot is realized by using a series chain of two caterpillar wheels on which 24-suction pads are installed. White each caterpillar wheel rotates on the vertical plane surface, the vacuum pads are activated in sequence based on the sequential opening by specially designed mechanical valves. The detail design feature of the valve is also described in this paper. The overall size of the robot is around 460 mm in width and length, respectively, and 200 mm in height. Its mass is slightly over 14 kg. The main mechanical structure of the robot consists of driving motors, vacuum caterpillar system, steering part, vacuum pump and battery. The performance of the robot is verified on the vertical wall.