• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.5B
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• pp.498-507
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• 2004

The fast and Precise service for the users request is the most important in the World Wide Web. However, the lest service is difficult due to the rapid increase of the Internet users recently. The Shared Web Caching (SWC) is one of the methods solving this problem. The performance of SWC is highly depend on the hit rate and the hit rate is effected by the memory size, processing speed of the server, load balancing and so on. The conventional load balancing is usually based on the state history of system, but the prediction of the state of the system can be used for the load balancing that will further improve the hit rate. In this study, a Hot Spot Prediction Method (HSPM) has been suggested to improve the throughputs of the proxy. The predicted hot spots, which is the item most frequently requested, should be predicted beforehand. The result show that the suggested method is better than the consistent hashing in the point of the load balancing and the hit rate.

• Journal of the Korea Convergence Society
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• v.11 no.1
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• pp.285-291
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• 2020

There is a growing interest in breast augmentation surgery, which can most effectively maximize femininity, among modern women around the world. However, breast augmentation surgery is considered one of the most terrifying surgeries many women are afraid of, as many cases of its side effects have been reported. As a way to provide a complementary method to deal with it, this study investigated the effects of a non-surgical breast enhancement program by stretching soft tissue of the breast. According to the results, there was no change in body weight and breast elasticity, but there were marked increases in breast cup size, breast diameter and volume of the women who used this program. The external soft tissue expansion system was found to be effective in Korean women's change of breast shape. On the other hand, users should use this system regularly for some period of time, and this would limit their social activities. Therefore, for the effective use of this system, its users should make individual efforts.

• Journal of IKEEE
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• v.14 no.3
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• pp.190-198
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• 2010

This paper describes a auto focus piezo actuator driver IC for portable digital camera. The 80[V] DC voltage is generated by a DC-DC converter and supplied to power of piezo moving control circuit. The voltage of piezo actuator needs range -20[V] to 80[V] proportional to 1[Vp-p] input control voltages. The dimensions and number of external parts are minimized in order to get a smaller hardware size. IIC(Inter-IC) interface logic is designed for data interface and it makes debugging easy, test for mass productions. The power consumption is around 40[mW] with supply voltage of 3.6[V]. This device has been fabricated in a 0.6[um] double poly, triple metal 100[V] BCD MOS process and whole chip size is 1600*1500 [$um^2$].

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.7
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• pp.659-664
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• 2016

In this paper, we suggest operational trans-conductance amplifier(OTA) for current-mode FIR filter that can be used in a digital circuit system requiring high operating frequency and low power consumption. The current-mode signal processing is one of the very innovative design method for a low power consumption system with high operating frequency because it shows a constant power regardless of frequency. From the simulation result using 0.35um CMOS process, when Vdd is 2V, it is confirmed that the proposed circuit showed the dynamic range of the about 1V, about 50% of supply voltage and output current swing of about 0~200uA. Also, the power consumption was evaluated with about 21uW and the active size for an integration was measured with $71um{\times}166um$.

• Transactions of the Society of Information Storage Systems
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• v.1 no.2
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• pp.127-131
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• 2005

We report a nanometer scale mark formation using a $PtO_x$ thin film or a TbFeCo rare-earth transition metal film and the mechanism. The multi-layer samples($ZnS-SiO_2/PtOx/ZNS-SiO_2,\;ZnS-SiO_2/TbFeCo/ZnS-SiO_2$) were prepared with a magnetron sputtering method on a polycarbonate or a glass substrate. By laser irradiation of approximately a few nanoseconds, nanometer scale marks were fabricated. During the fabrication process, the thin films were thermally reacted or inter-diffused during the laser irradiation. 75 nm bubble marks in the PtOx multi-layer sample by an approximately 4-ns laser irradiation. Inside the bubble mark, Pt particles with a few nanometer sizes are distributed. The $50{\sim}100$ nm bubble marks in the TbFeCo multi-layer sample by a few nanosecond laser irradiations. We will report the detail structure of the samples, the bubble mark formation process and the mechanism.

• Korean Journal of Construction Engineering and Management
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• v.8 no.3
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• pp.106-115
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• 2007

The size and length of road tunnels have been gradually expanded as industry developed. Consequently, the risk has been increased. The decision making process for ventilation system for road tunnels involves a large amount of information on economic feasibility, construction methods, and safety etc. In situation where systematically structured decision making process is unavailable, almost decisions about ventilation systems are made based on engineers' private knowledge and experiences. Procedure and criteria to choose the best optimized ventilation system among many alternatives are proposed, breaking away from the economic dependency-oriented decision making. This paper presents a Multi-Attribute Utility Theory and AHP based function with which planners can calculate overall utility of each alternative. It is anticipated that the effective use of the proposed methodology for decision making on ventilation systems ould be able to reduce the likelihood of the occurrence of potential safety risks as well as increase the overall ventilation performance.

• Journal of Digital Contents Society
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• v.18 no.8
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• pp.1621-1626
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• 2017

This study conducts data visualization of common climax patterns of Korean blockbuster films to analyze shots and evaluate scene (subplot unit) arrangement. For this purpose, a model of editing patterns is used to analyze how many climax patterns a film contains. Moreover, a system, which automatically collects shot images and classifies shot sizes of collected data, is designed to demonstrate that a single scene is composed based on a climax pattern. As a scene is a subplot and thus its arrangement cannot fully be analyzed only by climax patterns, dialogues of starring actors are also used to identify scenes, and the result is compared with data visualization results. It detects dialogues between particular actors and visualizes dialogue formation in a network form. Such network visualization enables the arrangement of main subplots to be analyzed, and the box office performance of a film can be explained by the density of subplots. The study of two types comparison analysis is expected to contribute to planning, plotting, and producing films.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.1
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• pp.60-71
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• 1998

The propagation environment is effected by Rayleigh fading, Rician fading, path loss and lognormal shadowing in microcellular mobile radio system. In these surroundings we analysed the performance on received Rician signals among L Rician interferers and the characteristics of lognormal shadowing for various parameters such as reuse distance, cluster size, signal to interference power ratio and protection ratio using outage probability. We also studied various channels Rayleigh signal and Rician interferer, Rician signal and Rayleigh interferer, Rician signal and Rician interferer and so on using outage probability. The theoretical extention and computer simulation effectively analysed the characteristic of lognormal shadowed Rician channel.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.4
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• pp.501-506
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• 2008

Statistical POS tagging is prone to error, because of the inherent limitations of statistical data, especially single source of data. Therefore it is widely agreed that the possibility of further enhancement lies in exploiting various knowledge sources. However these data sources are bound to be inconsistent to each other. This paper shows the possibility of using maximum entropy model to Korean language POS tagging. We use as the knowledge sources n-gram data and trigger pair data. We show how perplexity measure varies when two knowledge sources are combined using maximum entropy method. The experiment used a trigram model which produced 94.9% accuracy using Hidden Markov Model, and showed increase to 95.6% when combined with trigger pair data using Maximum Entropy method. This clearly shows possibility of further enhancement when various knowledge sources are developed and combined using ME method.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.5
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• pp.477-483
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• 2011

Existing switching system that is one of the ways which are used for DC/DC power converter is classified to hard-switching system and resonant-soft-switching system, generally. Hard-switching system is inefficient because the power loss of the switching element is large when it is been to trun on or turn off. And resonant-soft-switching system have the defect that need to add the another reactor and capacitor that make it expensive and huge. This paper suggest the ZVS Full-Bridge power converter contrcution of novel switching system for the overcoming these shortcomings. In Suggested soft-switching system, the front of buck converter at diode current, switch is changing on and off at the part of full-bridge converter's zero voltage part. as the result that is possible to be ZVS excepting the reactor and capacitor. also to verify the reasonability of the isolated ZVS full-bridge DC/DC converter as previously suggested, we produced the 500[W] level DC/DC converter and enforced the simulation for Psim, and then it able to conform the superiority of the DC/DC converter's efficient.