• Journal of Astronomy and Space Sciences
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• v.17 no.2
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• pp.233-240
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• 2000

Five scientific instruments are planned on KAISTSAT-4 that is scheduled to be launched in 2002. A far ultra-violet imaging spectrograph and a set of space plasma instruments are currently being designed. The imaging spectrograph will make observations of astronomical objects and Earth's upper atmosphere. The plasma instrumentation is capable of fast measuring the thermal magnetosphere plasmas, cold ionospheric plasmas and the Earth's magnetic fields. Major system drivers and constraints on the payloads as well as the spacecraft are identified. A preliminary analysis of the K-4 mission has been undertaken with the system requirements that are derived from the system drivers. Detailed investigation shows that Sun-synchronous orbits with approximate altitudes of 800km are optimal to satisfy the identified requirements. Comparisons with other orbits of different inclinations are also shown. Four operation modes and a daily schedule of spacecraft maneuver are found from the Sun-synchronous orbital model. It is shown that the scientific objectives of K-4 can be achieved with moderate levels of design and operation risks.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.199-204
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• 2005

The decrease of summer peak electric load of our country is very important. The government is arranging a lot of support policies and statutes. etc. to decrease of peak electric load. And ice storage system is known as one of the alternatives. The purpose of this study is to collect basic data for operating characteristics to plan the most suitable operation of capsule-type ice storage system. The storaging tank is designed to take charge 40% of total cooling load in building, In operation condition the storage tank took charge 50%. Coefficient Of Performance of daily screw refrigerator is around 4.

• Journal of Korean Neurosurgical Society
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• v.30 no.7
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• pp.939-942
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• 2001

Thirty nine-year-old man who required urgent shunt operation due to rapidly deteriorating visual acuity suffered from ventriculitis after aneurysmal operation. Daily dose of 20mg of vancomycin and amikyn were given intraventricularly via external ventricular catheter after failure of various kinds of systemic antibiotics. The exit of the catheter was made on the upper chest wall to prevent superinfection. External ventricular drainage could finally be switched to ventriculo-peritoneal shunt and he was discharged with clinical improvement.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.224-225
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• 2010

This paper proposes a battery energy storage system using a photovoltaic generation system. The proposed system consists of a grid, battery and PV array. Considering a daily load profile, radiation and battery, operation modes are divided. An algorithm is presented based on modes. In the paper, operation modes and algorithms are verified through simulations.

• The Journal of Information Systems
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• v.30 no.1
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• pp.105-121
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• 2021

Purpose Today, through digital services, many people enjoy a conveient and comfortable life. Nevertheless, it is easy to find people in our daily lives who are buried in work without any payment that we did not do before digital services. Such un-payed works under digital environment are called digital shadow works. The purpose of this study is to classification and dynamics of digital shadow works and to suggest research direction. Design/methodology/approach Based on two dimension, voluntary participation ('should' type and 'want' type) and work orientation (management-operation), digital shadow works were classified into four categories - chore, makeup, routine, and quest. Findings In digital shadow work there are four types of dynamics - routine and quest, makeup and chore, makeup and quest, and quest and actions in offline. According to the classification and analysis of dynamics, three research directions in digital shadow work are suggested and discussed- digital shadow works operation mechanism considering dynamics, expansion of existing user theories based on survey method by digital shadow works and social influences by digital shadow works.

• Journal of the Korean Operations Research and Management Science Society
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• v.1 no.1
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• pp.111-125
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• 1976

This study investigates the one-year performance of the Seoul Metropolitan Rail Transit(SMRT) operation. It intends to provide a basic understanding for railway operation in Seoul Metropolitan Area and thereby for making rational transport policy. The paper is conceptually comprised of four sections; analysis of passenger travel characteristics; SMRT costing and traffic cost function: its operating characteristics in terms of finance and utilization; primary social benefits of SMRT and suggestions. In the first year of operation (1974), the average daily traffic was about 335,000, After the drastic increases of fare in both Subway and KNR rail-lines, the travel volume has been cut by almost 10 percent, though most pronounced on intra-Subway line. The spatial distribution of passengers indicates that travelers use the SMRT line mainly for uninterrupted direct travel toward the CBD. In the prospective costing, the opereting expenses are divided into three groups; those which vary directly with volume; those partially variable with volume; and those entirely unrelated to volume change, With this information, cost function was derived for varying schedules of operation. Primary social benefits of the SMRT are assessed, though preliminary. Account should be taken of the nature of common costs of the SMRT in fare-rate making, especially when much of the operating expenses are accounted for by the fixed costs such that the revenue may not readily turn into break-even. The accounting results of the one-year operation coincide reasonably well with the prospective costing estimates. According to the findings of this annd another travelers' behavior studies, managerial effort would bring more revenue gain to the SMRT than fare increase does, not to speak of greater social benefits by so doing.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.6
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• pp.421-428
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• 2021

Lithium-ion secondary batteries exhibit advantageous characteristics such as high voltage, high energy density, and long life, allowing them to be widely used in both military and daily life. However, the lithium-ion secondary battery does have its limitation; for example, the output power and capacity are readily decreased due to the increased internal impedance during discharging at a lower temperature (-32℃, military requirement). Also, during charging at a lower temperature, lithium dendrite growth is accelerated at the anode, thereby decreasing the battery capacity and life as well. This paper describes a study that involves increasing the internal temperature of lithium-ion secondary battery by energy circulation operation in a low-temperature environment. The energy circulation operation allows the lithium-ion secondary battery to alternately charge and discharge, while the internal resistance of lithium-ion battery acts as a heating element to raise its own temperature. Therefore, the energy circulation operation method and device were newly designed based on the electrochemical impedance spectroscopy of the lithium-ion secondary battery to mediate the battery performance at a lower temperature. Through the energy circulation operation of lithium ion secondary battery, as a result of the heat generated from internal resistance in an extremely low-temperature environment, the temperature of the lithium-ion secondary battery increased by more than 20℃ within 10 minutes and showed a 75% discharging capacity compared with that at room temperature.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2001.10a
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• pp.286-289
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• 2001

This paper deals with the procedures of effective mid-term Operation Planning establishment for painting shop in shipbuilding. and develop prototype system. In general, the block painting process consists of two stages such as blasting operation for surface preparation and painting operation for paint application for blocks. Weather condition is a potent Influence on those operations. The procedures consists of four steps, Load analysis, Generate alternative simulation plan. Implementation of Allocation automation module and Compare result of each simulation plan. Explain of each step. as follows, 1.step, Load analysis measure amount of assigned workload and manhour. 2.step, simulation scheme include alterable control variable such as overtime, weather. Auto allocating module carry out feasibility of simulation plan. 3.step, Allocation automation module are composed of three algorithms, as followings: - the block allocation algorithm that determines the number of blocks to be processed each day, - the team allocation algorithm that allocates blocks to worker groups. - the block arrangement algorithm that arrange blocks in blasting and painting cells. Since the block arrangement algorithm is conducted simultaneously with the team allocation algorithm, the total structure of the operating algorithms is considered to have two phases: first, daily load balancing with capacity limit and second, team allocation considering arrangement each day 4 step, Comparing result of each simulation plan. and select best simulation plan.

• Journal of Korea Multimedia Society
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• v.10 no.6
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• pp.786-798
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• 2007

As we go about our daily lives, people often collect surrounding information and adapt to the situation. Computer development trends show that one wants computers to work like human beings, i.e. computers can sense its context and adapt corresponding to context changes. To implement this expectation, a context aware service layer is needed. In this layer, sensors capture its environment and send this information to the service center. Considering received information as its context, the service center seeks the suitable operation according to the context. Tills paper presents a context aware service which is applied in controlling air-conditioner. The air-conditioner includes sensors which are installed at some special positions in a room. Each of these sensors gathers comfort-influenced information like temperature, humidity and sends them to air-conditioner. The air-conditioner adapts its operation to the environment according to the sensed information. To control the air-conditioner effectively, we use a genetic algorithm which is suitable in adaptation issues. The simulation shows that the room condition can be maintained at a comfortable level by using context-aware services in the operation of the air-conditioning system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.10
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• pp.28-37
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• 2011

Though Korea has introduced CBP(Cost Based pool) power trading system since 2001, long-term Generation system planning has been executed by government for Cost minimization every 2 years. Until currently the model which is used for Generation system planning and best-mix only considers cost minimization and total yearly or quarterly electricity demand every year. In a view point of one day power supply operation, technical characteristics, like the ramp up/down rate of total generation system, minimum up/down time and GFRQ(Governor Free Response Quantity), are very important. this paper analyzes Optimal Fuel-Mix for 2022 Korea generation system satisfying these constraints of each fuel type and considering pump storage plants, construction cost and $CO_2$ emission charge Using MILP(Mixed Integer Linear Programming) method. Also the sensitivity analysis which follows in future power industry environmental change accomplished.