• Journal of the Korea Society for Simulation
• /
• v.17 no.2
• /
• pp.63-74
• /
• 2008

The design of best efficient production process is common requirements of the production strategy department and the process planning department to maximize the revenue and accomplish target production volumes in the production periods. And they use several general methods for that-line-balancing, removing of the bottle-neck process, facility ramp-up, increasing of the worker's utilization, etc. But, those methods have depended on analytic, static and arithmetic calculations, yet. So, irregular work-waiting time causing the delay time isn't include in extracting production capacity, especially in the line production process. The work-waiting time is changed irregularly along the variation of each machine and very important for calculate real product lead-time and forecasting target production volumes. At this thesis, i'm going to mention the importance of the delay time of conveyor system which can be extracted by discrete-event simulation. And suggest it as a new main variable that must be considered at designing new production system. Then experimented and tested that's effects in the H-company case, conveyor based line production process.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.8B
• /
• pp.637-646
• /
• 2012

Recently, Wireless Sensor Networks (WSNs) are used in many applications. When sensor nodes are deployed on special areas, where humans have any difficulties to get in, the nodes form network topology themselves. By using the sensor nodes, users are able to obtain environmental information. Due to the lack of the battery capability, sensor nodes should be efficiently managed with energy consumption in WSNs. In specific applications (e.g. in intrusion detections), intruders tend to occur unexpectedly. For the energy efficiency in the applications, an appropriate algorithm is strongly required. In this paper, we propose tree-based routing algorithm for the specific applications, which based on the intrusion detection. In addition, In order to decrease traffic density, the proposed algorithm provides enhanced method considering link cost and load balance, and it establishes efficient links amongst the sensor nodes. Simultaneously, by using the proposed scheme, parent and child nodes are (re-)defined. Furthermore, efficient routing table management facilitates to improve energy efficiency especially in the limited power source. In order to apply a realistic military environment, in this paper, we design three scenarios according to an intruder's moving direction; (1) the intruder is passing along a path where sensor nodes have been already deployed. (2) the intruders are crossing the path. (3) the intruders, who are moving as (1)'s scenario, are certainly deviating from the middle of the path. In conclusion, through the simulation results, we obtain the performance results in terms of latency and energy consumption, and analyze them. Finally, we validate our algorithm is highly able to adapt on such the application environments.

• Journal of the Korea Society for Simulation
• /
• v.28 no.2
• /
• pp.107-117
• /
• 2019

Because shipbuilding is single-product production with limited resources, production management technology is essential to manage the resources effectively and maximize the productivity of ship-process. Therefore, many shipbuilding companies are conducting research on ship production plan and process considering various constraints in the field by applying modeling and simulation. However, it is difficult to provide accurate production plan on sudden schedule and process changes, and to understand the interconnectivity between the processes that produce blocks in existing research. In addition, there are many differences between the production planning and field planning because detailed processes and quantity of blocks can not be considered. In this research, we propose the integrated process-based modeling method considering process-operation sequences, BOM(Bill of materials) and resource constraints of all the scheduled blocks in the indoor system. Through the integrated process-based model, it is easy for the user to grasp the assembly relationship, workspace and preliminary relationship of assembly process between the blocks in indoor system. Also, it is possible to obtain the overall production plan that maximizes resource efficiency without the separate simulation and resource modeling procedures because resource balancing that considers the amount of resource quantity shared in the indoor system is carried out.

• Transactions of the Korean hydrogen and new energy society
• /
• v.25 no.5
• /
• pp.509-515
• /
• 2014

At the fuel processing system (FPS) of fuel cell vehicle, hydrogen recirculation blower (HRB) is used for the recirculation of remained hydrogen after reaction. In this paper, noise and vibration improvement of HRB is studied by changing design and control. It is checked the campbell diagram and critical speed for stability of rotor, and housing stiffness is improved using simulation of frequency response function (FRF). A method is suggested that can decrease the unbalance amount of the rotor and impeller which main source of noise and vibration. In order to reduce the noise during deceleration of blower, electrical braking is applied and tested the risk impact of durability. Founded the optimum switching frequency of the motor control, and reduced the idle rpm by increasing of aerodynamic performance. The superiority of paper is proved by measurement of the improved product's noise and vibration.

• 한국신재생에너지학회:학술대회논문집
• /
• 2009.06a
• /
• pp.353-356
• /
• 2009

A pivotal mechanical balance of plant for 75kW class molten carbonate fuel cells comprise of a catalytic burner and an ejector which has been designed and tested in KEPRI(Korea Electric Power Research Institute). The catalytic burner, which oxidizes residual fuel in the anode tail gas, was operated at several conditions. Some problems arose due to local overheating or auto-ignition, which could limit the catalyst life. The catalytic burner was designed by considering both gas mixing and gas velocity. Test results showed that the temperature distribution is very uniform. In addition, an ejector is a fluid machinery to be utilized for mixing fluids, maintaining vacuum, and transporting them. The ejector is placed at mixing point between the anode off gas and the cathode off gas or the fresh air Several ejectors were designed and tested to form a suction on the fuel tail gas and balance the differential pressures between anode and cathode over a range of operating conditions. The tests showed that the design of the nozzle and throat played an important role in balancing the anode tail and cathode inlet gas pressures. The 75kW MCFC system built in our ejector and catalytic burner was successfully operated from Novembe, 2008 to April, 2009. It recorded the voltage of 104V at the current of 754A and reached the maximum generating power of 78.5kW DC. The results for both stand-alone and integration into another balance of plant are discussed.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.17 no.3
• /
• pp.3885-3893
• /
• 1975

This work was intended to study the cutting graph and vibratory phenomina of a newly developed mower which may be suitable for mowing agricultural product having large and hard stems like corn and sugar beet. The system consists of cutter-bar having Curvilinear-translation motion, which attached to drag-crank mechanism. The motion of equation developed for experimental vibratory system which equipped with the cutter-bar system was established and the parameters defining the system's vibratory motion were experimentally determined. The optimum balancing weight for the cutter-bar am vibratory characteristics of the cutter-bar for various counterweight were analyzed to provide the design and operational conditions. The results of the study are summarized as follows; (1) The cutting graph by the new cutter-bar system depends upon the magnitude of ratio of forward travel(Vm) to crank speed (R$\omega$); The cutting pitch for Vm/R$\omega$ 1 (whole cycle cutting) and Vm/R$\omega$=2/$\pi$ (a half cycle cutting) are 2$\pi$ Vm and 4R, respectively. (2) The experimental vibratory system had been proved to function adequately so that it can be used in determining the required counterweight to minimize the vibratory motion of cutter-bar. (3) Experimentally determined counterweight to give the least vibratory motion was a little greater than the theoretically determined one. With the optimum counterweight it was possible to reduce up to about 87% of the amplitude without counterweight, which may be considered to be within safe operational region. (4) To avoid the actual operation of the cutter-bar at resonance which occured in low frequency ratio, it was considered that the rotational speed of the crank for a specific design of mower should be determined separately in connection with the desired cutting graph.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.17 no.2
• /
• pp.111-124
• /
• 2015

This study inferred the symbolism of shaman's costume in China from shamanism and types of shaman's costume in Naje, Deokgang-hyun, Guiju-seong, China through field survey. Shamanism in China has complicated aspects due to negotiations with other culture for a long time while maintaining its own consistency based on ethnicity. Symbolism of shaman's costume in Naje, Guiju-seong, China is observed as follows. First, the shaman's costume in China appears differently from every Jangcha in relation to the position of god appearing in Jangcha when Tolosa takes the position of god as a symbol of sex and god. In Naje of China, the most important shaman's costume indicating the position of god has a unique mask for every deity. It communicates that Tolosa wearing a costume appropriate for the god of wine shall become the god in that Jangcha. Second, the shaman's costume in China has something to do with Yin-Yang and the five elements theory of Taoism as a symbol of shamanism visio of the universe and system of reason. Most of Tolosas hosting Naje are men but dress up as women by wearing Nagun looking like a skirt. Nagun is usually red, the color of Yang, which symbolizes that by wearing such costume that takes color of Yang, Tolosa expels an ominous thing by balancing yin and yang and taking god's strong power. Third, Tolosa takes an eight-breadth Nagun, as a symbol of people. An eight-breadth worn by Tolosa in Naje strengthens the spirit of union and fight of the Tujia nationality who live in Deokgang-hyun, Guiju-seong through folk legends. In this course, a symbolic meaning of the national spirit has been provided on an eight-breadth Nagun, a shaman's costume.

• Journal of Korean Society of Transportation
• /
• v.27 no.6
• /
• pp.147-156
• /
• 2009

We present a methodology for modeling and solving the transit frequency design problem with variable demand. The problem is described as a bi-level model based on a non-cooperative Stackelberg game. The upper-level operator problem is formulated as a non-linear optimization model to minimize net cost, which includes operating cost, travel cost and revenue, with fleet size and frequency constraints. The lower-level user problem is formulated as a capacity-constrained stochastic user equilibrium assignment model with variable demand, considering transfer delay between transit lines. An efficient algorithm is also presented for solving the proposed model. The upper-level model is solved by a gradient projection method, and the lower-level model is solved by an existing iterative balancing method. An application of the proposed model and algorithm is presented using a small test network. The results of this application show that the proposed algorithm converges well to an optimal point. The methodology of this study is expected to contribute to form a theoretical basis for diagnosing the problems of current transit systems and for improving its operational efficiency to increase the demand as well as the level of service.

• Journal of Korea Game Society
• /
• v.11 no.6
• /
• pp.33-42
• /
• 2011

In this study, game-aided human life type game design method is suggested. It mainly deals with the permissiveness of the game rules and coenesthesia of the game that are fitted with the agility of the elders such as the performance of a selective response. And 'Rolling hoops Balance Game' has been implemented by applying the game-aided human life type game. Since the pressure sensors are installed on each parts of the chair type game controller, to play the game, a gamer simply uses her hands and feet to press the sensors without requirements of the complex movements. The goal of the game are the leg muscles strength and improvement of the body balancing ability. In addition, the game graphics consists of sensory stimuli package(Namazi, Haynes, reminiscence therapy, 1994) to make friendly mood for elders. We have tested 50 elders who were more than 65 years old. 74% of them answered they were satisfied totally for the game play. It is a meaningful result that 88% of participants replied they would like to play the game again.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2009.05a
• /
• pp.95-98
• /
• 2009

RFID(Radio Frequency IDentification) technology is an automatic identification method using radio frequencies between RFID reader which collects the informatin and tag which transmits the information. RFID technology develops passive RFID which transmit the only ID to active RFID which transmit the additional information such as sensing information. there is ISO/IEC 18000-7 as typical standard of active RFID. it is single channel system of 433.92MHz and has limitation of collection of a number of tags. to overcome limitation of collection of many tags, we propose the new 2.4GHz active RFID technology which can use the multi-channel. if reader has multi-interface and uses another channel in each, reader could fast collect the tags. but, if a reader which has many interfaces collects tags through the specific interface, the performance may not improve any more comparing with a reader using single interface. in this paper, we show the fast collection through design and implementation of protocol for load balancing between interfaces in multi-interface RFID reader.