• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.591-593
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• 2016

Device-to-device (D2D) communications underlaid cellular infrastructure is an competitive local area services technology to promote spectrum usage for next generation cellular networks. These potential can only be tap through efficient interference coordination. Previous works only concentrated on interference from D2D pairs whiles interference from CUs to D2D pairs were neglected. This work focus on solving uplink interference problem emanating from multiple CUs sharing its resource with multiple D2D pairs. The base station (BS) acting as a supervisor selfishly institute a pricing scheme to manage the interference it experience from D2D pairs based on its Quality of service (QoS) requirement. D2D pairs following the supervisor make power allocation decisions considering the price from the BS in a non-cooperative game fashion. In order for the D2D pairs to also meet their QoS requirement, they suggest a price to the BS called discount price which reflects the interference they receive from the CUs. Finally, we analyze the proposed approach.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.1
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• pp.61-69
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• 2005

The topology of NPC inverter coupled with the large number of devices used increases the probability of device failure. It's necessary to develop an optimal remedial strategy which can be used to continue the application when fault occurs. The fault tolerance is obtained by the use of the proposed method. The proposed method utilizes that the one phase load with the failed power device could be connected to the center-tap of the DC-link capacitor in order to dc-link voltage with balance and the sinusoidal phase current with constant amplitude under the single power device fault condition. The strategy described in this paper is expected to provide an economic alternative to more expensive redundancy techniques.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.1
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• pp.51-58
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• 2016

As semiconductor technology has developed, device performance has been improved. However, since device structures became smaller, circuit aging due to operational and environmental conditions can be accelerated. Circuit aging causes a performance degradation and eventually a system error. In reliable systems, a failure due to aging might cause a great disaster. Therefore, these systems need a performance degradation prediction function so that they can take action in advance before a failure occurs. This paper presents an on-line circuit performance degradation monitoring scheme for predicting a failure by detecting performance degradation during circuit normal operation. In our proposed scheme, IEEE 1149.1 output boundary scan cells and TAP controller are reused. The experimental result shows that the proposed architecture can monitor the performance degradation during normal operation without stopping the circuit.

• Journal of environmental and Sanitary engineering
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• v.6 no.1
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• pp.7-25
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• 1991

Until now, pure drinking water grnerally menas the water without taste, odor, general bacteria, coliform, and other exotic substance. Such a definition has been changing recently due to the finding of numerous other inorganic and organic substances unknown to us. 10 years ago, major causes of death were infectious agents and parasites contained in water, but recently, it has become apparent that some substances contained in drinking water cause cancer and heart diseases. We must drink about 2L of water everyday in order to maintain healthy condition. Waters used for drinking include tap water, well water, spring water, filtered water, etc., but the quality of drinking water has more polluted due to the industrial development and population increase. For example, industrial waste waters from industrial plants pollute the water supply sources ; toxic substances contained in the waste waters pollute the ground water sources by penetrating the geological strata, and municipal, livestock, public building waste waters also pollute the water supply sources. Sometimes, the polluted surface waters were announced to be polluted by various kinds of orgainc substance, and it is reported that the pollution of ground water by orga nic substances has few in number but high in its concectration comparing with those of surface water. As the water quality pollution level increases, so the amount of disinfectant also increase. For example, chlorine solution, one of widely used disinfectants, creates trihalomethane(THM), a carcinogen, and halogen compounds. According to Oliver, through chlorine disinfection process, humine substance and chlorine create bolatile organic halide and nonvolatile organic halide by chemical reaction. There are tens or hundreds filtering devices, but filtering principles and maintenance metjhods are different, so their efficiency tests are needed. According to Smith, the effeciency tests aginst over 30 Ameican filtering devices show that 10 devices can remove 85% of volatile organics and further studies on filtered waters are underway. In consideration of important impacts of polluted drinking water on national health, authors studied the state of water quality pollution against tap water used as drinking water, filtration device passed water, ground water, and conserved drinking water ; tested the efficiency of filtration devices for tap water ; tried to sep up the detection method by using ion chromatography based on negative ion and positive ion by using single column, and attemped the simple filtration method for general households.

• Journal of Digital Convergence
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• v.11 no.11
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• pp.389-395
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• 2013

As fusing IT and medical technique, the number of patients who adhere medical equipment inside of them is increasing. However there is a problem of for the third person to tap or modulate the patient's biometric data viciously. This paper suggests quantum encryption-based key distribution model to share key for the third person not to tap or modulate the patient's biometric data between patient and hospital staff. The proposed model uses one-time pad key that shares key sending random bits not direct sending message of quantum data. Also, it guarantees patient's anonymity because the biometric data of injected-device in the body doesn't be exposed unnecessarily.

• Korean Journal of Optics and Photonics
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• v.14 no.6
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• pp.578-582
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• 2003

We propose a novel structure of wavelength selective optical add/drop module comprising two tap couplers and a fiber Bragg grating. The device has unique features including a simpler structure and a lower cost of implementation as compared with existing devices for the same operation. The module performance has been measured and analyzed experimentally. The implemented prototype module shows good performance with no-crosstalk power penalty in a 155 Mbps per channel wavelength-division-multiplexing transmission system but suffers from a relatively high loss of 3.5 ㏈ and 21 ㏈ for transmitted and dropped channels, respectively. While the dropped channel extinction ratio was more than 25 ㏈, the transmitted channel extinction ratio was more than 35 ㏈.

• Corrosion Science and Technology
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• v.23 no.3
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• pp.203-214
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• 2024

A heat exchanger is a device designed to transfer heat between two or more fluids. In a vehicle's thermal management system, Al heat exchangers play a critical role in controlling and managing heat for efficient and safe operation of the engine and other components. The fluid used to prevent heat exchangers from overheating the engine is mostly tap water. Heat exchange performance can be maintained at sub-zero temperatures using a solution mixed with antifreeze. Although the fluid flowing through the heat exchanger can reduce the temperature inside the engine, it also has various problems such as cavitation corrosion. Cavitation corrosion characteristics in tap water and corrosion characteristics were evaluated in this study when antifreeze was added for test specimens where AA4045 was cladded on the inner surface of AA3003 tubes of a fin-type heat exchanger. The cavitation corrosion resistance of AA3003 was found to be superior to that of AA4045 regardless of the test solution due to higher corrosion resistance and hardness of AA3003 than those of AA4045. The cavitation corrosion rate of Al alloys increased with the addition of antifreeze.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.4
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• pp.139-143
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• 2006

Recently, standard of living improved and Information-Communication industry developed rapidly. Thereby, interest about electric power quality is rising worldwide. So, research and Development to enhance electric power quality in various viewpoint until most suitable supply system from each kind device to improve electric power quality. And specially, interest about voltage quality is rising by diffusion increase of information communication appliance and minuteness control appliance etc. Also Power consumption is increasing, but expansion of large size generator by environmental and site security problem is difficult. So, introduction of distribution generation is investigated actively by electric-power industry reorganization. Voltage management of power system had been controlled by ULTC (Under Load Tap Changer) in substation and pole transformer on the high voltage distribution line. But, voltage control device on substation and distribution line is applied each other separatively. Therefore, efficiency of line voltage control equipment is dropping. Also, research about introduction upper limit of distribution generation is consisting continuously. This paper presents cooperation use way between voltage control device and introduction upper limit of distribution generation for most suitable voltage control in distribution power system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.233-234
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• 2021

The freezing of the water meter due to the cold wave in winter causes safety accidents caused by freezing and suspending the supply of tap water and various inconveniences. In this study, the water meter develops a test device similar to the environment in which the actual freezing occurs and tests repeatedly by changing the temperature, humidity, flow rate, pressure, valve improvement, pump operation status, etc. Based on the data obtained through this, it is planning to predict the timing of freezing by applying AI technology to correlation between freeze influencing factors.

• Journal of the Korean Magnetics Society
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• v.18 no.5
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• pp.174-179
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• 2008

The measurement dissolution sensor system using GMR-SV device with magnetic sensitivity of 0.8 %/Oe and Mg-film thick of 200 nm and Mg-foil thick of 50 mm was fabricated and characterized. During the water dissolving process of Mg-film and Mg-foil, the subtle variation of magnetic field by the decrease of current in solenoid was detected by the GMR-SV sensor. The variations of Mg bubble number and ORP as a function of time for three different kinds of edible, tap, and distilled water, are measured and compared. A After 45 min, the speed of fast dissolving Mg was shown the order of edible > tap > DI water. The variation of output magnetoresistance as a function of dissolved time of Mg-film and Mg-foil for edible water, which is composed of mineral content of $0.8{\sim}5.4\;mg/l$ was investigated. The response times for the dissolution in edible water were 5 min and 20 min, respectively. From the measurement of dissolving time and speed for Mg-film and Mg-foil using GMR-SV device, the mineral Mg sensor system in edible water can be possible to develop.