• 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 Korean Society of Food Science and Nutrition
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• v.39 no.8
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• pp.1102-1106
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• 2010

This study was carried out to investigate the effect of ethanol extract from citrus peels (CP-Et) against the alloxan-induced oxidative damage on HIT-T15, Hamster pancreatic $\beta$-cell. Total polyphenol and flavonoid contents in CP-Et were $57.00{\pm}2.91\;mg/g$ and $8.11{\pm}2.83\;mg/g$, respectively. Cell toxicity on HIT-T15 by CP-Et (0.125~0.75 mg/mL) was not observed. CP-Et (0.125 mg/mL) increased cell proliferation rate of HIT-T15, which was treated alloxan ($IC_{50}=11.58\;mM$) (cell viability=$80.52{\pm}3.29%$ of normal cell, p<0.05). In comparison with insulin secretion of oxidative damaged HIT-T15, 1.5 fold ($116.93{\pm}2.11\;{\mu}g/mg$ protein) was increased by treatment CP-Et treatment (0.125 mg/mL) in HIT-T15 (p<0.05). These results showed that CP-Et contribute to repairing cells and improvement of insulin expression on oxidative stress pancreatic $\beta$-cell, and also suggested application of CP-Et as a functional food material for type 2 diabetes.

• Journal of Internet Computing and Services
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• v.10 no.2
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• pp.15-28
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• 2009

This paper proposes HWbF(Hit and WLC based Firewall) design which consists of an PFS(Packet Filter Station) and APS(Application Proxy Station). PFS is designed to reduce bottleneck and to prevent the transmission delay of them by distributing packets with PLB(Packet Load Balancing) module, and APS is designed to manage a proxy cash server by using PCSLB(Proxy Cash Server Load Balancing) module and to detect a DoS attack with packet traffic quantity. Therefore, the proposed HWbF in this paper prevents packet transmission delay that was a drawback in an existing Firewall, diminishes bottleneck, and then increases the processing speed of the packet. Also, as HWbF reduce the 50% and 25% of the respective DoS attack error detection rate(TCP) about average value and the fixed critical value to 38% and 17%. with the proposed expression by manipulating the critical value according to the packet traffic quantity, it not only improve the detection of DoS attack traffic but also diminishes the overload of a proxy cash server.

• Journal of the Korean Data and Information Science Society
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• v.24 no.6
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• pp.1421-1428
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• 2013

In this paper, we would like to test whether the hit at a particular bat has a dependency with the hitting results at the previous bats in professional baseball games. For this purpose, we used the 2011 Korean Baseball League data. We find out that the hitting percentage at a particular bat has no dependency with the hit at the previous bat, after reviewing the conditional probability of hit at each bat and the lift. From the independence test of hits at consecutive bats, and hit at a particular bat with no hits at previous bats, we can conclude that hits at particular bats are not dependent on the hits at previous bats in most cases. Hence, we can safely conclude that a hit at a particular bat is statistically independent from the hits at the previous bats.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.4
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• pp.499-505
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• 1998

In developing an automated surface inspect algorithm, we have designed a hierarchical classifier using neural network. The defects which exist on the surface of cold mill strip have a scattering or singular distribution. We have considered three major problems, that is preprocessing, feature extraction and defect classification. In preprocessing, Top-hit transform, adaptive thresholding, thinning and noise rejection are used Especially, Top-hit transform using local minimax operation diminishes the effect of bad lighting. In feature extraction, geometric, moment, co-occurrence matrix, and histogram ratio features are calculated. The histogram ratio feature is taken from the gray-level image. For defect classification, we suggest a hierarchical structure of which nodes are multilayer neural network classifiers. The proposed algorithm reduced error rate by comparing to one-stage structure.

• Journal of Broadcast Engineering
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• v.25 no.4
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• pp.576-586
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• 2020

Analyzing baseball games using sensors such as radars or riders is expensive. In this paper, we propose an algorithm to detect pitch shots and hit shots using baseball video and to generate ball trajectories within hit shots using camera movement. After the pitch shot and the hit shot detection using object detection and optical flow, we generate the transformation relationship between frames and ball locations in the frame, and calculates the ball trajectory. The performance of the proposed method is evaluated for three KBO baseball video sequences, and the detection accuracy and detection rate of pitch shot and hit shot were within 89-95 [%], and the average error for shot range was 13.6[m], The direction error was 7.5° and foul classification accuracy was 98.6%.

• Journal of the Korean Society of Visualization
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• v.16 no.1
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• pp.21-29
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• 2018

Homogeneous and isotropic turbulence (HIT) with no mean flow is a very useful type of flow for basic turbulence research. However, it is difficult to generate HIT in the lab. In this study, we implemented HIT in a confined box through synthetic jet actuators using sub-woofer speakers. Characteristics of HIT are varied depending on the strength of the jets. We used 2D PIV to measure the velocity field. Turbulence statistics such as homogeneity, isotropy ratio, turbulence kinetic energy, dissipation rate, Taylor microscale, Kolmogorov scale, and velocity correlation coefficient were calculated. Most of the turbulence statistics increased exponentially according to the strength of the jets, and the Taylor Reynolds number reached up to 185.

• Korean Journal of Materials Research
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• v.5 no.1
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• pp.12-21
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• 1995

The study was performed to study the effects of strain rate on acoustics emission( AE) during bulging test in corrosive environmentsynthetic sea water. The strain rates used were in the range $4 \times 10^{-6}S^{-1}$ to $1 \times 10^{-4} \times S^{-1}$ and the parameters used to evaluate AE signal characteristics were AE hit and amplitude. It can be observed that the cumulative AE hit and average amplitude during fracture process increase highly at decreasing strain rates while the equivalent fracture strain and the crack length of circumferencial direction become decrease. The peak point of AE signal characteristic parameters approach to the first half of test. When the average amplitude per unit equivalent fracture strain was above 20dB, it was definitly observed stress corrosion cracking phenomena. Additional, we knew that the AE test had the possibility to evaluate SCC susceptibility with various strain rates.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.4
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• pp.420-425
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• 2009

In this paper, image detection and recognition algorithms are studied with respect to embedded carrier system. There are many suggested techniques to detect and recognize objects. But they have the propensity to need much calculation for high hit rate. Advanced and modified method needs to study for embedded systems that low power consumption and real time response are requested. The proposed methods were implemented using Intel(R) Open Source Computer Vision Library provided by Intel Corporation. And they run and tested on embedded system using a ARM920T processor by cross-compiling. They showed 1.6sec response time and 95% hit rate and supported the automated moving carrier system smoothly.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.643-645
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• 2001

인터넷이라는 환경이 우리의 생활의 일부로 자리잡으면서, 급속히 늘어난 사용자들의 요구는 그 만큼 네트워크의 현저한 부하증가를 일으키고 네트워크의 성능저하를 유발하며 속도 면에서도 빠른 응답을 원하는 사용자들의 욕구를 충족시키지 못하게 된다. 이에 대한 하나의 대응책이, 프락시 서버를 사용함으로써 네트워크 대역폭을 효과적으로 절약하고 서버 측의 부하를 감소시키며 사용자의 요청에 대한 빠른 응답이 가능하게 하는 것이다. 그러나 프락시 서버는 제한된 캐시용량 때문에 새 개체를 위한 공간확보를 위해 기존 개체를 제거해야 하는데, 캐시의 성능을 최대화하도록 하는 효율적인 캐시대체 정책이 필요하다. 기존의 대체정책이 캐시성능판단의 두 기준인 히트율(Hit Rate)과 바이트히트율(Byte Hit Rate)을 만족시키지 못하던지 흑은 불필요한 개체에 공간을 낭비하는 등 최대한치 공간활용을 못하는 단점을 가지고 있다. 본 논문에서는 캐시를 상위층과 하위충의 2단계로 나누어 운용하면서, 상위층은 분할된 여러개의 파티션으로 관리하여 히트율과 바이트율을 높게 유지하고 하위층은 상위의 각각의 파티션들에 추가적으로 필요한 캐시공간을 제공함으로서 동적인 파티션공간분할 효과를 제공하는 프락시 서버의 캐시구조와 캐시대체정책을 제안한다.