• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.4
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• pp.1796-1802
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• 2011

In this paper, the radio propagation path loss prediction simulator in tunnel was developed. It used a image theory method for analysing precise radio propagation path. And it can predict radio propagation path loss in straight and curved tunnels. The simulator can plot realtime radio propagation paths using various parameters which was input by user. And it can simulate from changing transmitter and receiver positions. The predicted path loss of simulator was compared with the measurements in Chunhyun tunnel and confirmed the validity.

• Structural Engineering and Mechanics
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• v.83 no.6
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• pp.745-756
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• 2022

This study aims to determine the cause of the load resistance loss in storage racks that can be attributed to external forces such as earthquakes and to improve safety by developing reinforcement systems that can prevent load resistance loss. To this end, a static cyclic loading test was performed on pallet racks commonly used in logistics warehouses. The test results indicated that a pallet rack exposed to an external force loses more than 50% of its load resistance owing to the damage caused to column-beam joints. Three reinforcement systems were developed for preventing load resistance loss in storage racks exposed to an external force and for performing differentiated target functions: column reinforcement device, seismic damper, and viscoelastic damper. Shake table testing was performed to evaluate the earthquake response and verify the performance of these reinforcement systems. The results confirmed that, the maximum displacement, which causes the loss of load resistance and the permanent deformation of racks under external force, is reduced using the developed reinforcement devices. Thus, the appropriate selection of the developed reinforcement devices by users can help secure the safety of the storage racks.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.3
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• pp.33-38
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• 2010

In this paper, the nature of iron loss in electrical steel during alternating field excitation is investigated more precisely. The exact definition of AC iron loss is cleared by accurately measuring the iron loss for conditions of both the sinusoidal magnetic field and sinusoidal magnetic flux density. The results of this approach to iron loss calculations in electrical steel are compared to experimentally-measured losses. In addition, an inverse hysteresis model considering eddy current loss was developed to analyze the iron loss when the input is the voltage source. With this model, the inrush current in the inductor or transformer as well as the iron loss can be calculated.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.2
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• pp.186-192
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• 2012

Noise is a major cause of hearing loss in the air base. There are lots of risk factors of hearing loss including noise, and hearing loss can be accelerated by combined effects of these risk factors. Here in, we reviewed risk factors of hearing loss, and analysed key risk factors inducing hearing loss in the air base. Risk factors exacerbating hearing loss with noise were mainly investigated in this research because noise could not be an avoidable risk factor in the air base. Analysed data will contribute to make green environment minimizing hearing loss of pilots and supporting personnels in the air base.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.1
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• pp.77-82
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• 2003

The ac loss is an important issue in the design of high-Tc superconducting power devices such as transformers and cables. In these devices many Bi-2223 tapes are closely stacked together and exposed to alternating magnetic fields that can have different orientations with respect to a tape. In such arrangement the magnetization loss is influenced by the screening current induced in adjacent tapes and thus different from that in a single tape. This stacking effect was experimentally investigated by measuring the magnetization loss in a stack, which consists of a number of tapes. First the magnetization loss in the single tape was measured in order to confirm the reliability of the loss data measured in the stack. The results for the single tape coincide well will the loss characteristics described in other previous works. For the stack In parallel and longitudinal magnetic fields the measured loss is Independent of both the number of tapes and stacking type. The longitudinal magnetization loss Is well explained rather by the slab model for decoupled filaments. For the tall stack in perpendicular field the measured loss at low fields is greatly decreased, compared to the loss of the single tape. However the loss at high fields is unaffected. These loss behaviors in the tall stack are well described by the slab model for full coupling.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.1
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• pp.129-145
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• 2017

This study proposes a methodology to estimate the financial damages by personal information breach of a company and to analyse risk systematically through a case study of a company which experiences private information breach. Using FAIR(Factor Analysis of Information Risk) model, estimate the loss amount and to analyse risk objectively of a company by personal information breach. This study estimates adequacy and importance of corresponding factors applying AHP(Analytic Hierarchy Process) on each factors for assessing loss amount. By adopting proposed methodology in this study, the person in charge of actual work can assess and prove the loss amount though the latest risk estimation methodology. In addition, the person in charge can select the proper parameters for the corresponding company and can obtain the objective quantitative estimation. Hence it can be reported to the management by accurately assessing loss amount caused by personal information breach.

• Spatial Information Research
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• v.17 no.2
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• pp.243-249
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• 2009

Damages from typhoon events have contributed more than 60 percent of total economic and social loss and the size of loss have been increased up to 800 million dollars per year in Korea, It is therefore necessary to make an effort to mitigate the loss of natural disasters. To facilitate the evaluation of damages in advance and to support the decision making to recover the damages, scientific methods have been adopted. With the effort, GIS data can provide various tools. Three components of hazard mapping are estimation of hazard, inventory for vulnerable features, and fragility of each feature. Vulnerability of natural disaster can be obtained by relation between loss and meteorological data such as precipitation and wind speed. Features can be categorized from other GIS data of public facilities and private properties, and then social and economic loss can be estimated. At this point, GIS data conversions for each model are required. In this study, we build a method to estimate typhoon risk based on GIS data such as DEM, land cover and land use map, facilities.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.10
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• pp.483-493
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• 2001

The 3-phase induction is used for the MCP(main coolant pump) and the pure water is used for lubrication of bearing because of the difficulty of repair. Therefore the type of motor is the canned-motor that is welded by sealed can to prevent the stator and rotor from the lubricating water. A lot of Eddy currents are produced in the can because of the conductivity of material. And these eddy currents in the can are the most important cause that decrease the efficiency of induction motor. Therefore we have to find the method to decrease these eddy currents in the can for the improvement of efficiency of motor. In this paper, we proposed the method of design and analysis of canned-motor using equivalent circuit with consideration of can loss for the improvement of efficiency of motor.

• The Transactions of the Korea Information Processing Society
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• v.7 no.11S
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• pp.3675-3683
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• 2000

The Handoff is the core technical factor that is required when mobile host moves from one area to another, while transmitting and receiving data. The existing works try to minimize the loss of pockets by forwarding packets to the Cell which a mobile host will move to. However, though the loss quantity is little, the accumulated loss can del(rade the performance of the TCP, and can be a serious problem if data is sensitive to the loss of packets. In this paper, we can reduce a memory requesting in FA by restricting the mobile host to move within at most 2 movable cells and design the improved handoff protocol for Mil to receive packets seamlessly in spite of handoff. We can evaluate that the suggested method is superior to the previous method, as a result of comparing with it.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.16 no.2
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• pp.221-243
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• 2003

Sudden sensorineural hearing loss may be defined as a severe loss of hearing occurring within a short space of time without any obvious cause. Its etiology is not verified yet, treatment and prognosis are uncertain. Objectives: We reviewed 6 cases of patients who hospitalized in Kyunghee Oriental Medical Center Dept. of Otolaryngology. Using the criteria of Siegel and Research Team of the Japanese Ministry of Health and Welfare of Japan, We are to evaluate the effect of Herb medication, Acupuncture therapy, and Negative therapy. We also attempted to search effective methods of therapy of sudden sensorineural hearing loss. Methods: We treated them with Oyaksunki-san(烏藥順氣散) for softening qi-stagnation and supressing 'Wind'(順氣治風), Chungsimjihwang-tang(淸心地黃湯) for strengthening 'Heart' and 'Kidney'(補心益腎), Boikyangwi-tang(補益養胃湯) for strengthening 'Wi-qi' and 'Stomach'(補衛(胃)氣). We also used acupuncture therapy and negative therapy based on the textbook of Acupuncture and Moxibustion. Results: One patient recovered completely after 5 days therapy, two patient markedly, another two patient slightly and one patient had no improvement. Conclusions: To treat sudden hearing loss, we can use Oyaksunki-san(烏藥順氣散) in the early stage of the disease. We can treat with Chungsimjihwang-tang(淸心地黃湯) and Boikyangwi-tang(補益養胃湯) in the late period of the disease, and administer Jaeumgenby-tang(滋蔭健脾湯) for suppressing tinnitus. If there is evidence of viral infection and the patient have too severe hearing loss, We can also use steroid in combination with Herb medication in the early stage of the disease. The Western medicine demonstrated that the start time of treatment had influence on recovery. If we started Oriental medical treatment within a week from the onset of sudden deafness. we will obtain the desired results. As the Western medical treatment does, Oriental medical therapy may have no effect after one month from onset of the disease.