• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.4997-5006
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• 2010

A flash-memory-based SSDs(Solid State Disks) are one of the best media to support portable and desktop computers' storage devices. Their features include non-volatility, low power consumption, and fast access time for read operations, which are sufficient to present flash memories as major database storage components for desktop and server computers. However, we need to improve traditional storage management schemes based on HDD(Hard Disk Drive) and RAID(Redundant array of independent disks) due to the relatively slow or freezing characteristics of write operations of SSDs, as compared to fast read operations. In order to achieve this goal, we propose a new storage management scheme called Hetero-Mirroring based on traditional HDD mirroring scheme. Hetero-Mirroring-based scheme improves RAID-1 operation performance by balancing write-workloads and delaying write operations to avoid SSD freezing. Our test results show that our scheme significantly reduces the write operation overheads and freezing overheads, and improves the performance of traditional SSD-RAID-1 scheme by 18 percent, and the response time of the scheme by 38 percent.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.10
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• pp.46-51
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• 2007

The fault current limiting characteristics of superconducting fault current limiter(SFCL) using magnetic coupling of two coils were investigated. This SFCL consists of a high-TC superconducting(HTSC) element and two coils with series or parallel connection on the same iron. In normal time, the inner magnetic fluxes generated by two coils are canceled in case that the HTSC element keeps superconducting state. However, in case that the resistance of the HTSC element happens by a short-circuit the magnetic fluxes, not cancelled, induce the voltages across two coils and the fault current can be limited by the impedance of this SFCL. This SFCL has the merit that the operational current of SFCL can be increased higher than the critical current of the superconducting element by adjusting the inductance ratio between two coils. To confirm its operation, the circuit for the fault simulation was constructed. From the measured voltage and current of the SFCL, it was confirmed that the operating current of this SFCL increased more than that of HTSC element's independent operation.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.4
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• pp.387-394
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• 2016

Today, hot rolled mill plant are currently operating 24 hours a day. The main processes of hot-rolled steel mill are Reheating Furnace, Roughing Mill, Fishing Mill and the Down Coiler. In the process checking over the thickness and width of rolled material, temperature control is an important factor. It is quite often the cause of the work breakdown and find a bad elements for product. After the shipping out the product, when a claim occurs requires an investigation. In each process of the conventional thickness gauge, width, and thermometer. Operation by an independent data acquisition and this monitoring is problematic and straining of the operator. The monitoring process the data of each function and incorporate monitoring results can also check future work. The installation of this system will improve our efficiency and productivity. In the rolling process by developing more efficient operating quality monitoring system, this will be made possible.

• The Korean Journal of Emergency Medical Services
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• v.7 no.1
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• pp.235-246
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• 2003

Due to major disasters Korea has been damaged, and they caused lots of casualties: for last ten years natural disasters caused 1288 deaths including missing people; human disasters including industrial disasters brought as many as 4,512.148 casual ties (126,372 deaths with 4,385,400 injuries); and they cost 44.1 trillion property damage. However, even though major disasters have brought about tremendous human loss and property damage, Koreas National Disaster Medical System to rescue casualties is insufficient, and it has not been activated. Fortunately, through major disaster management process, the National Disaster Management System has been developed, increasing its own efficiency, and resulting in to organize an Office of Firefighting and Prevention of Disasters under the central government. Considering the value of human lives, the disaster medical part, in the U.S.A. as well as in Korea, must have an independent organization in the government, not as one sector of the government department. It will have its own organizational structure, such as disaster planning, operation, and logistics, and interact with central and local government or between local government agencies. So each agency will cooperate and supply resources interchangeably. Also, with the system of disaster management and restoration, the disaster medical system must be advanced in keeping step. Its role must be extended due to the possibility of biological terror or SARS around the world, resulting in severe casualties. Korea has the Emergency Medical Service System based on the regulation of emergency medical care, yet it is a part of the National Disaster Management System. It must be managed independently apart from it. As we see the emergency medical technicians playing as the backbone in disaster medical care in the US, we should have legal foundations for Koreas emergency medical technicians, emergency medical providers, to participate in rescue operation actively. At the same time, we need to have a national register system to classify disaster medical resources, and a total plan to place resources according to the impact of disaster, and how to organize teams. We also need to draw up a scheme to activate civil disaster medical resources, as integrating public and private or voluntary organizations.

• Journal of Korean Library and Information Science Society
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• v.4
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• pp.1-38
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• 1977

This paper intend to analyze, review and point out the actual conditions of "Reserve Book System" of university libraries in Korea, then to present several proposals. I took six national universities and six private universities as researching objects and the materials were collected by questionnaires. 1) There are so many libraries which have no seperate reserve books room, while every colleges, and their departments are putting into forces the reserve book system. This makes many unresonable problems. 2) Many volumes were not adequate to the courses of each depertment and so many problems arose to set up reserve books owing to Lhe lack of library budget. 3) Insincerities of professors and librarians make no good conditions for the reserve book system. 4) For insufficiency of understanding about the reserve book system cf professors and students with university authorities, we must persuade and guide them about this system. 5) We imust evaluate about the problems of the reserve book system. I show the methods which is necessary to solve the problems of this system in the following. 1) As to methods of improving the field of menagement for running about the reserve book system, a) Establishment of the independent reserve books room. b) Gradual expansion of the reserve book system. c) Evaluation of the actual using of reserve books. 2) As to contents to improve the reserve book system, a) Improving the selection method of reserve books. b) Increasing the library budget enable to purchase more reserve books. c) Making more close connections between the curricula ard reserve books. 3) Settlment of coordinating system for carrying out reserve book system, a) We must have mutual understanding and co-operation among university authorities, faculties and libraries. b) We must have co-operation between professors and librariars.ibrariars.

• Archives of Craniofacial Surgery
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• v.9 no.2
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• pp.67-71
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• 2008

Purpose: Orbital floor fracture has open wound to maxillary sinus and if the patient has chronic maxillary sinusitis, it may be have more risk of infection, complications. The purpose of this comparative study is to be the effectiveness of prophylactic antibiotics in orbital floor fracture with chronic maxillary sinusitis. Methods: We studied 20 patients who diagnosed as orbital floor fracture with chronic maxillary sinusitis from march, 2005 to may, 2006. Among them 16 were male, 4 were female and age was ranged from 15 to 68, average was 42. A day before operation, Prophylactic antibiotics were used to 10 patients. Prophylactic antibiotics were not used to 10 patients. We defined control group as prophylactic antibiotics injection group a day before operation. After surgery, we confined use of same antibiotic for 7 days in both group. After 6 month from surgery, we compare the degree of enophthalmos from healthy side to legion side with hertel exopthalmometry(Inami, Japan) in control group and non-prophylactic antibiotics injection group. Results: In control group, comparison of discrepancy between enophthalmic eyeball and normal eyeball with Hertel exophthalmometer was 1.1 mm and non-prophylactic antibiotics injection group was 2.1 mm. In independent sample t-test, control group was showed statistically significant difference with non-prophylactic antibiotics injection group(p=0.007). Conclusions: In orbital floor fracture with chronic maxillary sinusitis, bacteria in maxillary sinus can increase post-operative complication by infecting infraorbital soft tissue, and it is thought to be antibiotic prophylaxis is play a role in decrease in degree of enophthalmos. We feel the need to further study of prophylactic antibiotics in orbital floor fracture with chronic maxillary sinusitis.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.2
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• pp.277-282
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• 2020

The construction of medium-and large-sized microgrid systems by unit area, which is being promoted worldwide, is being developed and expanded in the form of efficient operation of electric grids and independent operation in preparation for power emergencies. Therefore, for the development of the domestic electricity industry, it is urgent to analyze the current status and technology of relevant international standardization, and to make international standardization of domestic standard (draft) on the matters that need to be enacted and newly established. Campus microgrid implements smart grid element technologies such as Integrated Energy Management System(EMS), Distributed Power(DG), Energy Storage System(ESS), Demand Response(DR), and Electric Vehicle(EV) in a university campus. As a system that reduces energy use and improves energy use efficiency and energy independence, standardization is established to secure interoperability and reliability of such systems.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.4
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• pp.307-314
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• 1998

A novel high power factor Dual Half Bridge Series Resonant Inverter (DHB-SRI) for an induction heating appliance with multiple loads is proposed to remove the interferential acoustic noise caused by the difference between operating frequencies of adjacent loads. The circuit enables independent full power range control of two induction heating elements by one inverter circuit and has minimum switching losses due to the zero voltage switching characteristic. According to the mode analysis, I will explain the operation of the proposed circuit. To evaluate the required cooling capacity, loss analysis is performed through deriving some loss equations. In order to obtain the power factor correction capability and to lessen the system size, suitable design guides are given. Using the designed values, the proto-type circuit with 2.8kW power consumption for each induction heating element is built and tested to verify the operation of the proposed circuit.

• Korean Institute of Interior Design Journal
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• v.22 no.1
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• pp.47-54
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• 2013

For the office work environmental design, the importance of the design management is increased to improve operation efficiency as well as the aesthetic environmental implementation of the function today. Lighting is a required element ineffective operation environment. It has become more important for the aesthetic, economic, and practical reasons, to consider the luminous environment and the lighting of visual tasks separately. When the brightness is insufficient, productivity deteriorates, and the layout of the lighting located by mistake causes the fatigue of eyes. Productivity rises to office in a large number of studies so as satisfaction is low in general in the dark office, and to be bright. Therefore the purpose of this research is to suggest the right direction of lighting design of office building area. 11newly renovated office buildings are selected for this luminous environment research. We could conclusions as following through this research. First, it was planned brighter than the recommended lighting level in the most space. It shows that the accurate lighting design criteria is needed in order to achieve proper lighting environment. Second, the application of the LED lighting fixtures is continuously increased in the recent office lighting environment. It is explained that it is applied for reasons of the electrical energy reduction and the maintenance efficiency with the long life time. Third, the consideration of the lighting plan for the difference of working types is not enough. with various communication configuration through an independent plan, and the effective lighting plan that appropriateness preparation design and energy saving area vailable must be applied. Fourth, the lighting environment of the lobby needs a specialized lighting plan as are presentative space of the building.

• Journal of Internet Computing and Services
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• v.19 no.2
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• pp.17-26
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• 2018

Recently, through the emergence and convergence of Internet services, the unified Internet of thing(IoT) service platform have been researched. Currently, the IoT service is constructed as an independent system according to the purpose of the service provider, so information exchange and module reuse are impossible among similar services. In this paper, we propose a operation based service classification algorithm for various services in order to provide an environment of unfied Internet platform. In implementation, we classify and cluster more than 100 commercial IoT services. Based on this, we evaluated the performance of the proposed algorithm compared with the K-means algorithm. In order to prevent a single clustering due to the lack of sample groups, we re-cluster them using K-means algorithm. In future study, we will expand existing service sample groups and use the currently implemented classification system on Apache Spark for faster and more massive data processing.