• KIEAE Journal
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• v.14 no.5
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• pp.67-73
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• 2014

This study aims at examining kinetic efficient shading systems and their implementation methods. These days, the importance of the shading devices are getting more significant due to the energy problem. Cordially, suitable shade designs are required as an important element for the exterior envelope of the building. This study employs the optimal shading design as an efficient shading method with the kinetic system that can be converted actively by the altitude of the sun. The proposed kinetic shading system works not only as a lightshelf in case the altitude of the sun is high but also as a vertical louver when the sun is getting lower in order to block the direct sunlight. This study has analyzed the thermal performance and shading coefficient of the kinetic shading system in comparison to existing fixed shading devices using the Ecotect. The results, in sum, conclude that the suggested kinetic shading system could decrease direct sunlights 26.2% more than the existing shading methods.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.3001-3006
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• 2008

Recently, the internal combustion engines have focused on reducing both the CO2 emissions in order to cope with severe regulations for greenhouse effect. Therefore, various new technologies have been developed in many countries. Among them, the cooling system is spotlighted because it has great effect on fuel efficiency. However, the present engine cooling system is almost same as one of the 50 years ago. The needs for high performance and compact size make it important to improve engine cooling system, down-sizing and control method of coolant flow. Thus, low fuel consumption technology such as control and synthetic management of cooling system was necessary to satisfy with these needs. In this study, we applied electric thermostat to improve the fuel economy. The fuel consumption was compared after driving FTP-75 mode on both conditions which were with a conventional wax thermostat and with a electric thermostat. The coolant temperature of opening the electric thermostat is higher.

• Journal of the Korea Society for Simulation
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• v.11 no.2
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• pp.45-53
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• 2002

The main idea behind the Intelligent Networks(IN) concept is the separation of switching functionality from the service control, in order to meet various service requirements of subscribers and development of new services in time. In (N+1) type Intelligent Network with FEP-BEP framwork, each SCP-BEP system maintains its own subscibers' database respectively. In this case, DB updating operations at each SCP-BEP should be peformed concurrently such that DB updating method could affect the overall system performance. Moreover, it is not easy to predict the current system capacity to satisfy the future IN subscribers' service needs. In this paper, we discuss how much DB updating method affects the performance trends of (N+1) type Intelligent Network with FEP-BEP system by means of the simulation technique as the number of calls increase. The average turnaround time is used as a system performance measure.

• Journal of the military operations research society of Korea
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• v.16 no.2
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• pp.83-95
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• 1990

This paper addresses the problem of determining the optimal number of spares for a system consisting of multi-item parts. In commercial sector, the cost minimization is mainly considered as an objective functions in most inventory models. However, in the military inventory systems, it is more stressed on maximizing the system availability than minimizing the system cost because the field commander always wants the system to be in perfect working condition to prepare against an emergence case. In this point of view, this paper develops an inventory model which decides the optimal number of spares by minimizing units short and simultaneously achieving a certain level of system availability. Solution algorithms are derived using the generalized Lagrange multiplier approach and marginal analysis approach. Sample data and output results are provided and sensitivity analysis is performed as the level of system availability changes in order to decide the optimal number of spares and availability in terms of economic sense.

• Journal of Intelligence and Information Systems
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• v.8 no.2
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• pp.71-89
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• 2002

In this paper, an integrated planning system is introduced for the efficient operation of container terminal. It consists of discharging and loading planning, yard planning, and berth scheduling subsystem. This interface of this system is considered for user's convenience, and the rule-based system is suggested and developed in order to make planning with automatic procedures, warning functions for errors.

• 한국기계연구소 소보
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• s.13
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• pp.27-43
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• 1984

In order to obtain the high resilience, low compression set and less of hardness change in the wiper blade rubber, vulcanization system and receipes must be controlled. To improve the above the above Physical properties, the system should be taken as follows. i) peroxide vulcanization system and sulfur vulcanization system. ii) rubber having more cis-form than trans-form. iii) moderate particle size cabon black. v) usage of other improvement agent. The rubber blade with 4.4% compression set, 76% resilience, Hs 0 $\pm$ 2 hardness change could be abtained through vulcanization system, In addition, the surface of wiper blade must be treated by chemically and physically to minimize for the skid and friction.

• Journal of the Korea institute for structural maintenance and inspection
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• v.2 no.4
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• pp.194-200
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• 1998

Risk, probability of failure, which includes various uncertainties and influential factors of performance should be accounted for in engineering system. Recently, several different methods to analysis risk evaluation evolved and one of the practical method is FOSM (First Order Second Moment Method ). FOSM method is derived in terms of terms coefficient of variance to uncertainties which influence various factor. For risk evaluation and uncertainty analysis in hydraulic design system, load-capacity relationship is adopted in this paper. Sample catchment with design of sewer system is applied, which plots safety factor vs. risk. Risk evaluation and uncertainty analysis are very to important develop optimal design model in hydraulic system

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1020-1025
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• 2001

Vertical canned pumps are usually applied in the power plant to transport fluids that the available suction pressure is low at the condensate system and the circulating-water system. The top of the motor driver is 5.5m above the base and the barrel and drop column extend even further below the ground. While this size and configuration may produce an efficient pumping system, it also introduces several dynamic problems which must be considered in order to obtain a reliable operation. The main problem is that the vibrational mode of the long flexible cantilever structure above the ground exist near the operational characteristics of the condensate debris system. This system's trouble has been showed at 2,086 hp condensate water loading pumps in a nuclear power plant.

• Fire Science and Engineering
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• v.25 no.2
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• pp.138-143
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• 2011

In order to choose work system of fire organization between specialization system and multi- tasking system, fire organization's works should be analyzed. The most important thing of this task is evaluation of speciality of work that can be performed by estimating the duration of expertise of fire fighters' work. In this study I estimated the duration by survey. The duration is 12 years and 5 months which is a year and 9 months after promotion to fire senior sergeant lank in the case of average fire fighter.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.08a
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• pp.105-108
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• 2000

Many control techniques have been proposed in order to improve the control performance of discrete-time domain control system. In the position control system using a DC servo motor as a driver, the response-characteristic of system is controlled by the PID controller. In the PID control system, the transient response characteristic is more increased and settling time gets longer if gains of PID controller are unsuitable. In this paper, therefore, a expended PID control system is constructed by inserting a pre-compensator at output terminal of PID controller. It is implemented by using the double layers neural network. Form the results of computer simulation in the proposed control algorithm, its usefulness is verified.