• International journal of advanced smart convergence
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• 제2권1호
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• pp.6-11
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• 2013

Network Coding (NC) is a new paradigm for network communication. In network coding, intermediate nodes create new packets by algebraically combining ingress packets and send it to its neighbor node by broadcast manner. NC has rapidly emerged as a major research area in information theory due to its wide applicability to communication through real networks. Network coding is expected to improve throughput and channel efficiency in the wireless multi-hop network. Many researches have been carried out to employ network coding to wireless ad-hoc network. In this paper, we proposed a dynamic queue management to improve coding opportunistic to enhance efficiency of NC. In our design, intermediate nodes are buffering incoming packets to encode queue. We expect that the proposed algorithm shall improve encoding rate of network coded packet and also reduce end to end latency. From the simulation, the proposed algorithm achieved better performance in terms of coding gain and packet delivery rate than static queue management scheme.

• 한국기계가공학회지
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• 제10권2호
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• pp.9-15
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• 2011

In order to develop a practical postprocessor for 5-axis machining, the general equations of numerically controlled (NC) data for 5-axis configurations with not only non-orthogonal rotary axes but also orthogonal rotary axes were exactly expressed by the inverse kinematics, and a Windows-based postprocessor written in Visual Basic was developed according to the proposed algorithm. The developed postprocessor is a general system that suitable for all kinds of 5-axis machine tool with orthogonal and non-orthogonal rotary axes. Through implementation of the developed postprocessor and verification by a cutting simulation and machining experiment, the effectiveness of the proposed algorithm is confirmed. Compatibility is improved by allowing exchange of data formats such as rotational tool center position (RTCP) controlled NC data, vector post NC data, and program object file (POF) cutter location (CL)data, and convenience is increased by adding the function of work-piece origin offset. Consequently, the technology of practical post-processor for 5-axis machining is developed.

• 한국정밀공학회지
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• 제18권3호
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• pp.53-60
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• 2001

Water jet cutting is a new technology using very high pressure water as a cutting tool. Water jet cutting system consists of water preparation part, pressure generation pate, cutting head, and motion part. A PC-based numerical controlled (PC-NC) X-Y table is developed and water get cutting system is installed thereon. Water jet machining is applicable to various kinds of materials ranging from soft materials such as rubber and meat to hard-to-cut materials such as titanium. This paper shows the application of the abrasive waterjet system to titanium cutting.

• 한국군사과학기술학회지
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• 제20권4호
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• pp.514-519
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• 2017

To develop a gun propellant composition with high insensitivity and high energy, we formulated a composition by adding RDX into the nitrocellulose(NC) based propellant. The flame temperature of the RDX added NC(RAN) propellant was higher than that of neat NC propellant. The kinetic muzzle energy of RAN propellant was close to that of JA2 propellant at room temperature($21^{\circ}C$). The difference of kinetic muzzle energy of RAN propellant between high and room temperature settings as well as between a low and room temperature settings were less compared to those of JA2 propellant.

• 한국재료학회지
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• 제29권5호
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• pp.317-321
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• 2019

We investigated the characteristics of nano crystalline silicon(nc-Si) thin-film solar cells on graphite substrates. Amorphous silicon(a-Si) thin-film solar cells on graphite plates show low conversion efficiency due to high surface roughness, and many recombination by dangling bonds. In previous studies, we deposited barrier films by plasma enhanced chemical vapor deposition(PECVD) on graphite plate to reduce surface roughness and achieved ~7.8 % cell efficiency. In this study, we fabricated nc-Si thin film solar cell on graphite in order to increase the efficiency of solar cells. We achieved 8.45 % efficiency on graphite plate and applied this to nc-Si on graphite sheet for flexible solar cell applications. The characterization of the cell is performed with external quantum efficiency(EQE) and current density-voltage measurements(J-V). As a result, we obtain ~8.42 % cell efficiency in a flexible solar cell fabricated on a graphite sheet, which performance is similar to that of cells fabricated on graphite plates.

• 동아시아식생활학회지
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• 제15권5
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• pp.549-557
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• 2005

Effects of Acanthopanax senticosus extract (AS) on blood sugar content and serum lipid profiles of streptozotocin-induced diabetic rats were investigated. Experimental groups were classified into four groups, that is, normal control (NC) group, diabetic mellitus (DM) group, AS-fed group and DMAS-fed group. The AS group showed lower feed efficiency than the NC group, but the efficiency of DMAS group was higher than DM group. DMAS group showed the decreased water intake and urine by $45.5\%$ and $23.7\%$ respectively, compared with DM group. Compared with DM group, DMAS group decreased blood sugar by $46.9\%$ and triglyceride by $17.8\%$, total cholesterol by $10.0\%$ and LDL cholesterol by $22.0\%$ in serum, but increased serum HDL cholesterol by $14.4\%$ The relative percentage of liver or kidney per body weight, and the serum ALT activity in DMAS group were lower than those of DM group. There were no significant differences in hepatic glutathione(GSH) contents and total xanthine oxidase(XOD) activities among experimental groups. The hepatic lipid peroxide(LPO) content in DMAS group decreased by $54.6\%$ compared with that in DM group. The XOD (O type) and the ratio of O type to total type of both STZ-treated groups (DM and DMAS) were higher than those of NC group, but less conversion of D to O type was observed in DMAS group than in DM group. There was no significant difference in GST activity between NC and AS, but STZ-treated groups showed lower glutathione S-transferase(GST) activity than NC. In conclusion, it seems that AS reduces blood sugar by inhibiting the activity of xanthine oxidase type O as an oxygen-free radical generating system which induces the tissue damage. Antidiabetic effect of AS may regulate diabetes-induced high lipid profiles in blood.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.585-590
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• 1999

• 한국식품과학회지
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• 제31권4호
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• pp.999-1004
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• 1999

밤에서 추출한 천연 밤전분(NCS)과 이에 propylene oxide를 반응시켜 제조한 hydroxypro-pyl화 밤전분(HCS)의 이화학적 특성을 비교 검토하였다. 색도는 NCS와 HCS 사이에 별 차이가 없었고, 물결합 능력은 NCS가 233.8%, HCS가 244.5%를 나타내어 HCS의 물결합 능력이 증가하는 양상을 보였다. Hydroxypropylation에 의해 HCS의 청가 및 amylose 함량이 다소 감소하여 전분의 구조가 변형됨을 알 수 있었고 팽화력과 용해도에서도 증가하였다. 0.2% 전분 현탁액으로 광투과도를 측정한 결과 역시 HCS가 NCS에 비해 증가함을 알 수 있었다. DSC와 amylogram을 이용하여 호화 양상을 측정한 결과 hydroxypropylation에 의해 HCS의 호화 온도 및 호화 엔탈피가 감소하여 HCS를 식품가공에 이용할 경우 전분이 호화되는데 필요한 열량이 감소하여 경제적인 잇점이 있을 것으로 생각된다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 Handout for 2000 Inter. Machine Tool Technical Seminar
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• pp.61-70
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• 2000

This paper described the current status of machine tool technology and its future trends with a particular emphasis on high-speed machining. People in machine tool industry have continuously sought to serve fast-changing manufacturing industry with economical machining solutins. At presents, it appears that more productivity gain is demanded to shorten time-to-market and machining requirements become more stringent. In this regard, this paper firstly addressed a high-speed spindle as a key element for the next-generation machine tools. The sequel to it apparently went to high-speed feed axes and final discussion included the problem of how to optimize overall system including servo function. Lastly a brief look to NC technology including machine intelligence was taken.

• 한국발생생물학회지:발생과생식
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• 제18권1호
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• pp.43-49
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• 2014

Three species of Nortamea concinua (NC) and Haliotis discus hannai (HDH) from Tongyeong and Sulculus diversicolor supertexta (SDS) are widely distributed on the coast of the Yellow Sea, southern sea and Jeju Island in the Korean Peninsula under the innate ecosystem. There is a need to understand the genetic traits and composition of three mollusk species in order to evaluate exactly the patent genetic effect. PCR analysis was performed on DNA samples extracted from a total of 21 individuals using seven decamer oligonucleotides primers. Seven primers were shown to generate the unique shared loci to each species and shared loci by the three species which could be clearly scored. A hierarchical clustering tree was constructed using similarity matrices to generate a dendrogram, which was facilitated by the Systat version 10. 236 specific loci, with an average of 56.3 per primer, were identified in the NC species. 142 specific loci, with an average of 44.7 per primer, were identified in the HDH species. Especially, 126 numbers of shared loci by the three species, with an average of 18 per primer, were observed among the three species. Especially, the decamer primer BION-75 generated 7 unique loci to each species, which were identifying each species, in 700 bp NC species. Interestingly, the primer BION-50detected 42 shared loci by the three species, major and/or minor fragments of sizes 100 bp and 150 bp, respectively, which were identical in all samples. As regards average bandsharing value (BS) results, individuals from HDH species (0.772) exhibited higher bandsharing values than did individuals from NC species (0.655). In this study, the dendrogram obtained by the seven decamer primers indicates three genetic clusters: cluster 1 (CONCINNA 01~CONCINNA 07), cluster 2 (HANNAI 08~HANNAI 14), cluster 3 (SUPERTEXTA 15~SUPERTEXTA 21). Comparatively, individuals of HDH species were fairly closely related to that of SDS species, as shown in the hierarchical dendrogram of genetic distances.