• Journal of ILASS-Korea
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• v.20 no.3
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• pp.195-201
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• 2015

This study discusses a fuel injector test bench containing a mechanical type fuel supply system for heavy duty diesel engine. The main focus of this study was to evaluate the design stability of the test bench, which basically measures the injector durability of a multi-hole heavy duty injector by using pure diesel as a test fuel. In this experiment, diesel spray was controlled by a specially designed control box and all the experiments were carried out to measure e.g. fuel injection pressure and fuel injection quantity to understand the injection status which is interlinked with the stability factor of total test bench design. Also, the durability test was performed to understand the heavy duty operation lastingness of the designed system and the flow rate of the installed distributor pump in the fuel supply system of this studying test bench was compared with LO-1 and LO-2 pump. The results of the above mention tests revealed that the injector test bench design and control system can serve the purpose for heavy duty injector.

• Journal of Korea Multimedia Society
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• v.24 no.9
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• pp.1211-1223
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• 2021

Internet of Things(IoT) services have increased the demand for connectivity among electronics devices. As a result, various types of novel wireless communication technologies have been standardized and developed. In this paper, we evaluate the performance of low power wireless communication technologies such as Bluetooth, IEEE 802.15.4, DASH 7, IEEE 802.15.4g, LoRa, and SigFox in various environments. This is the first experiment evaluating various low power wireless communication technologies in real testbed. We expect that the evaluation results will be useful data to other researchers in applying the IoT technology in the future.

• Journal of information and communication convergence engineering
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• v.16 no.2
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• pp.93-98
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• 2018

The Internet of Things (IoT) is a form of the emerging 4th industry in the 5G era. IoT is expected to develop naturally in our daily life in the 5G era in which high-speed communication will be completed. Along with the rise of IoT, concerns about security and malicious attacks are also increasing. This paper examines DoS attacks, which are one of the representative security threats of IoT and proposes a local detection and blocking system that are suitable for response to such attacks. First, systems of the LoRaWAN type, which are most actively researched in the IoT system field and DoS attacks that can occur in such systems were examined. Then, the inverse order tree algorithm using regional characteristics was designed as a cluster analysis form. Finally, a system capable of defending denial-of-service attacks in the 5G IoT system using local detection and blocking with the Euclidean distance was designed.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.6
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• pp.869-879
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• 2012

This study was conducted to investigate the effects of dietary lipid source and level on growth performance, blood parameters, fatty acid composition and flesh quality of sub-adult olive flounder Paralichthys olivaceus. Eight experimental diets were formulated to contain 5% squid liver oil (SLO), 5% linseed oil (LO), 5% soybean oil (SO), a mixture of 1% squid liver oil, 2% linseed oil and 2% soybean oil (MIX), no lipid supplementation with high protein level (LL-HP), 10% squid liver oil (HL-SLO), a mixture of 1% squid liver oil, 4.5% linseed oil and 4.5% soybean oil (HL-VO), and 1% squid liver oil with high starch level (LL-HC), respectively. Two replicate groups of fish (average initial weight of 296 g) were fed the diets for 17 wks. After 5 wks, 11 wks and the end of the feeding trial, five fish from each tank were randomly sampled for analysis of body composition. At the end of the feeding trial, final mean weight of fish fed the LL-HP diet was significantly (p<0.05) higher than that of fish fed the HL-VO diet, but did not differ significantly from those of fish fed the SLO, LO, SO, MIX, HL-SLO and LL-HC diets. Fish fed the LL-HP diet showed significantly higher feed efficiency than fish fed the LO, HL-SLO and HL-VO diets. Feed efficiency of fish fed the LO, SO and MIX diets were similar to those of fish fed the SLO and HL-SLO diets. Fish fed the HL-SLO diet showed significantly higher total cholesterol content in plasma compared with other diets. Fatty acid composition of tissues was reflected by dietary fatty acid composition. The highest linoleic (LA) and linolenic acid (LNA) contents in the dorsal muscle were observed in fish fed the SO and LO diets, respectively, regardless of feeding period. The highest eicosapentaenoic acid (EPA) content in the dorsal muscle was observed in fish fed the LL-HP and LL-HC diets after 11 and 17 weeks of feeding, respectively. Fish fed the SLO and HL-SLO diets showed higher docosahexaenoic acid (DHA) content than that of other treatments after 11 and 17 weeks of feeding, respectively. Dietary inclusion of vegetable oils reduced n-3 HUFA contents in the dorsal muscle and liver of fish. The n-3 HUFA contents in tissues of fish fed the SLO and HL-SLO diets were higher than those of fish fed other diets, except for the LL-HP and LL-HC diets. Hardness, gel strength, chewiness and cohesiveness values of dorsal muscle in fish were significantly affected by dietary lipid source. The results of this study indicate that fish oil in fish meal based diets for sub-adult olive flounder could be replaced by soybean oil and linseed oil without negative effects on growth and feed utilization.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.5
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• pp.445-450
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• 2010

This study investigated the effects of dietary lipid sources on growth performance and body composition of juvenile far eastern catfish, Silurus asotus. Three replicate groups of fish (average weight 3.6 g) were fed with one of the following experimental diets containing 10% beef tallow (BT), 5% BT plus 5% corn oil (CO), 5% BT plus 5% linseed oil (LO), or 5% BT plus 5% squid liver oil (SO) as the lipid source for 5 weeks. No significant difference was observed in the survival among groups. The weight gain of fish fed the LO (high in 18:3n-3) and SO (high in n-3 highly unsaturated fatty acid) diets was significantly higher than that of the fish fed the CO (high in 18:2n-6) and BT diets (P<0.05). The feed efficiency of fish fed LO and SO diets was significantly higher than that of the fish fed the BT diet (P<0.05), but not significantly different from that of the fish fed the CO diet. The protein efficiency ratio of fish fed the SO diet was significantly higher than that of fish fed the CO and BT diets (P<0.05), but not significantly different from that of fish fed the LO diet. The 18:1n-9 of whole-body polar lipid fraction in fish fed the BT diet increased compared to that of fish fed the other diets. Fish fed the CO and LO diets had significantly higher contents of 18:2n-6 and 20:4n-6, and 18:3n-3, than the fish fed the other diets in polar and non-polar lipid fractions, respectively (P<0.05). Significantly higher contents of 20:5n-3 and 22:6n-3 were observed in the whole-body polar lipid fraction of fish fed the SO diet compared with fish fed the other diets (P<0.05). The study results indicate that linseed oil and squid liver oil containing n-3 fatty acids are good dietary lipid sources for the growth of far eastern catfish.

• Korean Journal of Metals and Materials
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• v.49 no.10
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• pp.818-822
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• 2011

ZnO nanorods were grown on Au-coated Si substrates by vapor phase transport (VPT) at the growth temperature of $600^{\circ}C$ using a mixture of zinc oxide and graphite powders as source material. Au thin films with the thickness of 5 nm were deposited by ion sputtering. Temperature-dependent photoluminescence (PL) was carried out to investigate the optical properties of the ZnO nanorods. Five peaks at 3.363, 3.327, 3.296, 3.228, and 3.143 eV, corresponding to the free exciton (FX), neutral donor bound exciton ($D^{\circ}X$), first order longitudinal optical phonon replica of free exciton (FX-1LO), FX-2LO, and FX-3LO emissions, were obtained at low-temperature (10 K). The intensity of these peaks decreased and their position was red shifted with the increase in the temperature. The FX emission peak energy of the ZnO nanorods exhibited an anomalous behavior (red-blue-red shift) with the increase in temperature. This is also known as an "S-shaped" emission shift. The thermal activation energy for the exciton with increasing temperature in the ZnO nanorods is found to be about 26.6 meV; the values of Varshni's empirical equation fitting parameters are = $5{\times}10^{-4}eV/K$, ${\beta}=350K$, and $E_g(0)=3.364eV$.

• Journal of applied mathematics & informatics
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• v.41 no.5
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• pp.1115-1128
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• 2023

In this paper, a novel hybrid method for multi-focus image fusion is proposed. The method combines the advantages of wavelet transform-based methods and focus-measure-based methods to achieve an improved fusion result. The input images are first decomposed into different frequency sub-bands using the discrete wavelet transform (DWT). The focus measure of each sub-band is then calculated using the Laplacian of Gaussian (LoG) operator, and the sub-band with the highest focus measure is selected as the focused sub-band. The focused sub-band is sharpened using an unsharp masking filter to preserve the details in the focused part of the image.Finally, the sharpened focused sub-bands from all input images are fused using the maximum intensity fusion method to preserve the important information from all focus images. The proposed method has been evaluated using standard multi focus image fusion datasets and has shown promising results compared to existing methods.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.514-516
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• 2003

고배율 렌즈를 장착한 3차원 비접촉 측정 장비에서 컴퓨터 비전을 이용한 정밀도 높은 형상의 측정을 위해서는 선명한 영상 획득을 위한 정확한 초점 위치 결정이 선행되어야 한다. 본 논문에서는 정초점 위치를 찾기 위하여 수동형 초점 조절 방법을 사용한다. 각각의 렌즈 위치에서의 입력 영상에 대해 초점 위치 추적의 척도가 되는 초점값을 변형된 LoG 방법을 이용하여 측정하고, 측정된 초점값들의 렌즈 위치에 따른 분포 곡선에 대한 가우시안 정합을 적용한 정초점 위치 검색을 통해 최적의 초점 위치를 결정하는 기법을 제안한다.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.799-804
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• 1990

In the blade grinding process, Blade image is captured. It is captured in the environment with vibration, using monochrome CCD camera with high speed electronic shutter. The image is preprocessed using LoG filter and zero crossing. We used Hough transformation to detect straight lines from the preprocessed image. From the equations of detected lines, we calculated width between lines caused by grinders. This paper proposes automatic measurement of blade width to automate the process control of blade grinding line.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04b
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• pp.190-192
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• 2000

MMDBMS(Main Memory Database Management System)에서 사용되는 갱신기법중 퍼지 검사점을 지원하는 직접갱신 기법은 많은 양의 로그를 필요로 하며 회복 과정이 복잡하다는 단점이 있다. 본 논문에서는 퍼지 검사점을 지원하면서 저장해야 할 로그의 양을 줄이고 회복 과정이 단순한 회복 기법을 제안한다. 제안하는 회복 기법은 로그의 양을 줄이고 위해 철회된 트랜잭션의 로그를 비휘발성 메모리에 저장하지 않는 시스템 구조와 많은 양의 메모리를 사용하지 않는 POLUG(Page Oritented Logical Undo loG)를 사용하여 퍼지 검사점을 지원할 수 있는 장점을 가진다.