• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.8 s.350
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• pp.47-58
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• 2006

Due to the movement of nodes, ad-hoc networks suffer from the problems such as the decrease of data delivery ratio, the increase of end-to-end delay, and the increase of routing overhead. The backup routing schemes try to solve these problems by finding the backup routes during the route discovery phase and using them when a route fails. Generally the backup routing schemes outperform the single-path routing schemes in terms of data delivery ratio, end-to-end delay, and routing overhead when the nodes move rapidly. But when the nodes don't move rapidly, the backup routing schemes generate more routing traffics than the single-path routing schemes because they need to exchange packets to find the backup route. In addition, when the backup route fails earlier than the main route, it can not use the backup route because in many backup route algorithms, the backup route is found only at the initial route discovery phase. RBR(Reactive Backup Routing Algorithm) proposed in this paper is an algorithm that provides more stable data delivery than the previous backup routing schemes through the selective maintenance of backup route and the backup route rediscovery. To do that RBR prioritize the backup routes, and maintain and use them selectively Thus it can also decrease the routing overheads. Also, RBR can increase data delivery ratio and decrease delay because it reestablishes the backup route when the network topology changes. For the performance evaluation, OPNET simulator is used to compare RBR with the single-path routing scheme and some of the well known backup routing schemes.

• Composites Research
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• v.30 no.1
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• pp.46-51
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• 2017

Structural battery has been researched extensively to combine the functions of the battery and structure without gravimetric or volumetric increments compared to their individual components. The main idea is to employ carbon fabric as the reinforcement and electrode, glass fabric as the separator, and solid-state electrolyte which can transfer load. However, state-of-the-art solid-state electrolytes do not have sufficient load carrying functionality and exhibiting appropriate ion conductivity simultaneously. Therefore, in this research, a system which has both battery and load carrying capabilities using glass fabric separator and liquid electrolyte was devised and tested to investigate the potential and feasibility of this structural battery system and observe electric properties. It was observed that elongating separator decreased electrical behavior stability. A possible cause of this phenomenon was the elongated glass fabric separator inadequately preventing the penetration of small particles of the cathode material into the anode. This problem was verified additionally by using a commercial separator. The characteristic of the glass fabric and the interface between the electrode and glass fabric needed to be further studied for the realization of such a load carrying structural battery system.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06b
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• pp.273-278
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• 2007

검사점 및 복구 도구(Checkpointing & Recovery Facility)를 이용하여 임베디드 시스템에서 결함 허용(Fault Tolerance) 기법을 적용할 경우 쓰기 작업의 오버헤드로 인해 실용성이 크게 떨어지게 된다. 실시간 운영체제와 함께 어떠한 한계 상황에서 결함 허용 및 복구 도구가 오히려 시스템의 성능을 저하시키는 요인으로 작용하게 되면 이는 결국 쓸모없는 도구가 되어 사용되지 않을 것이다. 따라서 프로세스의 복구를 위해 저장하는 프로세스 이미지의 기록에 소요되는 시간을 크게 낮추어야만 비로소 검사점 도구가 그 진가를 발휘하게 될 수 있다. 본 논문에서는 NVSRAM(Non Volatile SRAM)을 검사점 및 복구 도구의 저장 장치로 활용함으로써 기존의 검사점 도구에서 성능을 저하시키는 주원인이었던 검사점 기록의 오버헤드를 개선하기 위한 연구를 수행하였다. 검사점 기록 시간을 줄이기 위한 방법으로 주 메모리에 저장된 프로세스의 복구와 관련된 데이터를 SRAM 특성을 갖는 비휘발성 저장 장치인 NVSRAM에 저장하여 디스크 접근에 소요되는 시간을 최소화시킴으로써 임베디드 시스템에서 실용적으로 사용 가능한 검사점 도구를 구현하였고, 이러한 연구의 결과를 검증하기 위해 기존 시스템에서 저장 장치로 사용되던 플래시 메모리, 주 메모리, 원격 메모리를 사용하는 경우의 성능과 NVSRAM을 활용할 때의 성능을 비교해 보았다. 본 연구에서 제안하는 결함 허용 도구는 실제 시스템에 적용하여 효과적인 성능을 발휘할 수 있을 것이며, 차세대 메모리를 이용한 결함 허용 도구의 연구에 기여를 할 수 있을 것으로 기대된다.ate첨가배지(添加培地)에서 가장 저조(低調)하였다. vitamin중(中)에서는 niacin과 thiamine첨가배지(添加培地)에서 근소(僅少)한 증가(增加)를 나타내었다.소시켜 항이뇨 및 Na 배설 감소를 초래하는 작용과, 둘째는 신경 경로를 통하지 않고, 아마도 humoral factor를 통하여 신세뇨관에서 Na 재흡수를 억제하는 작용이 복합적으로 나타내는 것을 알 수 있었다.으로 초래되는 복합적인 기전으로 추정되었다., 소형과와 기형과는 S-3에서 많이 나왔다. 이상 연구결과에서 입도분포가 1.2-5mm인 것이 바람직한 것으로 나타났다.omopolysaccharides로 확인되었다. EPS 생성량이 가장 좋은 Leu. kimchii GJ2의 평균 분자량은 360,606 Da이었으며, 나머지 두 균주에 대해서는 생성 EPS 형태와 점도의 차이로 미루어 보아 생성 EPS의 분자구조와 분자량이 서로 다른 것으로 판단하였다.TEX>개로 통계학적으로 유의한 차이가 없었다. Heat shock protein-70 (HSP70)과 neuronal nitric oxide synthase (nNOS)에 대한 면역조직화학검사에서 실험군 Cs2군의 신경세포가 대조군 12군에 비해 HSP70과 nNOS의 과발현을 보였으며, 이는 통계학적으로 유의한 차이를 보였다(p<0.05). nNOS와 HSP70의 발현은 강한 연관성을 보였고(상관계수 0.91, p=0.000), nNOS를 발현하는 세포가 동시에 HSP70도 발현함을 확인할 수 있었다. 결론: 우리는 cyclosporin A가 토끼의 25분간의 척수허혈에 대해 척수보호 효과가 있었으며 이는 HSP70의

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.72-72
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• 2009

전자부품의 내부접속 및 파워반도체의 다이본딩과 같은 1차실장에는 고온환경에서의 사용과 2차실장에서의 재용융방지를 위해 높은 액상선온도 및 고상선온도를 필요로 하여, Pb-5wt%Sn, Pb-2.5wt%Ag로 대표되는 납성분 85%이상의 고온솔더가 널리 사용되고 있다. 생태계와 인체에 대한 납의 유해성이 보고된 이래, 무연솔더에 대한 연구가 활발히 진행되어 왔으나, Sn-Ag-Cu계로 대표되는 Sn계 합금으로 대체 중인 중온용 솔더와는 달리, 고온용 솔더에 대해서는 대체합금에 대한 연구가 미흡한 실정이다. 대체재의 부재로 인해 기존의 납을 다량함유한 솔더로 1차실장이 지속됨으로서, 2차실장의 무연화에도 불구하고 전자부품 및 기기의 재활용에 큰 어려움을 겪고 있다. 지금까지 고온용 무연솔더로서는 융점에 근거해 Au-(Sn, Ge, Si)계, Bi-Ag계, Zn-(Al, Sn)계의 극히 제한된 합금계만이 보고되어 왔다. Au계 솔더는 현재 플럭스를 사용하지 않는 광학, 디스플레이 분야 등 고부가가치 공정에 사용되고 있으나, 합금가격이 매우 비싸며 가공성이 나빠 대체재료로서는 적합하지 않다. Bi-Ag계 솔더 또한 취성합금으로 와이어 및 박판으로 가공하는데 어려움이 크며, 솔더로서 중요한 특성중 하나인 전기전도도 및 열전도도가 나쁜 편이다. 이에 비해, Zn계 합금은 비교적 낮은 합금가격, 적절한 가공성과 뛰어난 인장강도, 우수한 전기전도도 및 열전도도를 지녀, 고온용솔더 대체재료의 유력한 후보로 생각된다.이전 연구에서, 필자의 연구그룹은 Zn-Sn계 합금을 고온용 무연솔더로서 제안한 바 있다. Zn-Sn계 합금은 충분히 높은 융점과 함께, 금속간화합물이 없는 미세조직, 우수한 기계적 특성, 높은 전기전도도 및 열전도도 등의 장점을 나타내었다. 본 연구에서는 기초합금특성상 고온솔더로서 다양한 장점을 지닌 Zn-30wt%Sn합금을 고온용 솔더의 대표적인 적용의 하나인 다이본딩에 적용하여, 접합부의 강도 및 미세조직, 열피로 신뢰성에 대해 분석을 함으로서 실제 공정에의 적용가능성에 대해 검토하였다. Zn-30wt%Sn을 이용해 Au/TiN(Titanium nitride) 코팅한 Si다이를 AlN-DBC(aluminum nitride-direct bonded copper)기판에 접합한 결과, 양측에 완전히 젖은 기공이 없는 양호한 다이접합부를 얻었으며, 솔더내부에는 금속간화합물을 형성하지 않았다. Si다이와의 계면에는 TiN만이 존재하였으며, Cu와의 계면에는 Cu로부터 $Cu_5Zn_8,\;CuZn_5$의 반응층을 형성하였다. 온도사이클시험을 통한 열피로특성평가에서, Zn-30wt%Sn를 이용한 다이접합부는 1500사이클 지점에서 Cu와 Cu-Zn금속간화합물의 사이에서 피로균열이 형성되며, 접합강도가 크게 감소하였다. 열피로특성 향상을 위해 Cu표면에 TiN코팅을 하여 Zn-30wt%Sn 솔더로 다이접합한 결과, Si다이와 기판 양측에 TiN만으로 구성된 계면을 형성하였으며, TEM관찰을 통해 Zn-30wt%Sn과 극히 미세한 접합계면이 형성하고 있음을 확인하였다. Zn-wt%30Sn솔더와 TiN층의 병용으로 2000사이클까지 미세조직의 변화 및 강도저하가 없는 극히 안정된 고신뢰성의 다이접합부를 얻을 수가 있었다.

• Journal of Food Hygiene and Safety
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• v.28 no.2
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• pp.181-187
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• 2013

Identification of main ingredients in starches has been investigated using physicochemical analysis method mainly. However, physicochemical properties such as particle size have limitations in determining the differences among mixed starches. Therefore, we developed a molecular biological method to identify materials used in starch, as a sample, 11 kinds of starches including sweet potato starch, potato starch, corn starch, and tapioca starch. DNeasy plant mini kit, magnetic DNA purification system, and CTAB methods were used to extract DNA from samples. After gene extraction, whole genome amplification (WGA) was performed to amplify the extracted DNA. Species-specific primers were used as followings: ib-286-F/ib-286-R (105 bp), Pss 01n-5'/Pss 01n-3' (216 bp), SS11b 3-5'/SS11b 3-3' (114 bp), and SSRY26-F/SSRY26-R (121 bp) gene for sweet potato, potato, corn, and tapioca, respectively. In this study, we could confirm the main ingredients using WGA and PCR method.

• The Korean Journal of Applied Statistics
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• v.33 no.1
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• pp.47-59
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• 2020

In this paper, we present the longitudinal Markov binary regression model with t-link function when its transition order is known or unknown. It is assumed that logit or probit models are considered in binary regression models. Here, t-link function can be used for more flexibility instead of the probit model since the t distribution approaches to normal distribution as the degree of freedom goes to infinity. A Markov regression model is considered because of the longitudinal data of each individual data set. We propose Bayesian method to determine the transition order of Markov regression model. In particular, we use the deviance information criterion (DIC) (Spiegelhalter et al., 2002) of possible models in order to determine the transition order of the Markov binary regression model if the transition order is known; however, we compute and compare their posterior probabilities if unknown. In order to overcome the complicated Bayesian computation, our proposed model is reconstructed by the ideas of Albert and Chib (1993), Kuo and Mallick (1998), and Erkanli et al. (2001). Our proposed method is applied to the simulated data and real data examined by Sommer et al. (1984). Markov chain Monte Carlo methods to determine the optimal model are used assuming that the transition order of the Markov regression model are known or unknown. Gelman and Rubin's method (1992) is also employed to check the convergence of the Metropolis Hastings algorithm.

• Journal of Conservation Science
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• v.28 no.1
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• pp.53-62
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• 2012

The archival objects are tangible evidence related to the public service. They are unique and offer information representing the specific events, time or person. The archival objects as modern cultural heritage do not have the guideline to classify, manage and conserve them. Especially, it is difficult to apply general conservation process for burial artifacts, because there are few study example of conservation for metal archival objects and they have complex administrative value. We tried to find suitable material and application method for consolidation of copper alloy archival object. We choose three kinds of wax and acrylic resin for burial artifacts and had done comparative analysis of their characterizations following kinds and coating methods. As a result of evaluation by several surface analysis such as optical microscope, measuring film thickness, adhesive strength, contact angle and yellowing test, acrylic resin can use to archival objects of copper alloy, effectively but the method of heating after dip-coating with Wax B used before can get best effect of consolidation.

• Journal of Conservation Science
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• v.31 no.2
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• pp.105-114
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• 2015

In this study, an advanced epoxy putty which was as a multi-purpose restoration material being used to restore missing parts in the artifact preservation treatment process was developed. For the purpose of addressing the issues including the workability issue resulting from high strength, the drooping issue resulting from long hardening time during work process and the issue of contaminating the surface of artifact resulting from stained material on tools or gloves, a property comparison was conducted with existing materials to examine the properties of restoration materials in the form of epoxy putty currently being frequently used. For the purpose of addressing the issues of existing materials and allowing the developed epoxy putty to have similar properties, two types of hardeners with different properties were selected to conduct property experiments. As for the hardeners, mercaptan type hardener and aliphatic amine type hardeners in the total of two types were selected for the development. The result showed that the two types were both in the form of paste and their hardening time of 5-10 minutes were about 3-10 times shorter than that of existing materials, thereby improving the work convenience. In terms of abrasion rate to increase workability, it was improved by about 3 times to allow effective and convenient use. As for the issue of contaminating the artifact surface during the process, white micro-balloon was added as filler to address the issue to reduce the oil ingredient to develop multi-purpose restoration material with low shrinkage & high workability in coloring, light weight and cutting force.

• The KIPS Transactions:PartD
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• v.15D no.6
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• pp.767-776
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• 2008

Microarray technology is extensively being used in experimental molecular biology field. Microarray experiments generate quantitative expression measurements for thousands of genes simultaneously, which is useful for the phenotype classification of many diseases. One of the two major problems in microarray data classification is that the number of genes exceeds the number of tissue samples. The other problem is that current methods generate classifiers that are accurate but difficult to interpret. Our paper addresses these two problems. We performed a direct integration of individual microarrays with same biological objectives by transforming an expression value into a rank value within a sample and generated rank-comparison decision rules with variable number of genes for cancer classification. Our classifier is an ensemble method which has k top scoring decision rules. Each rule contains a number of genes, a relationship among involved genes, and a class label. Current classifiers which are also ensemble methods consist of k top scoring decision rules. However these classifiers fix the number of genes in each rule as a pair or a triple. In this paper we generalized the number of genes involved in each rule. The number of genes in each rule is in the range of 2 to N respectively. Generalizing the number of genes increases the robustness and the reliability of the classifier for the class prediction of an independent sample. Also our classifier is readily interpretable, accurate with small number of genes, and shed a possibility of the use in a clinical setting.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.10
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• pp.957-964
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• 2010

The deactivated catalyzed diesel particulate filter-trap (DPF) was remanufactured by ultrasonic wave treatment with various prepared solutions, followed by active component re-impregnation, and the emission control performance and surface properties of remanufactured DPF were studied at various remanufacturing conditions. The proper ultrasonic wave cleaning time at various prepared solutions and optimal re-impregnation amounts of active component for the best emission control performance of DPF were investigated and its performance tests were also carried out with various temperatures for the conversions of CO, THC (total hydrocarbon) and PM (particulate matter) by catalytic reaction test unit using bypass gas from the diesel engine dynamo system. It was found that the emission control performance of DPF remanufactured with the high-temperature air washing, ultrasonic wave cleaning at acid/base solutions and active component re-impregnation method was recovered to 95% level of its activity compared to that of the fresh DPF, which was caused by removing the deactivating materials from the surface of the DPF, through the analyses of performance test and their surface characterization by Optical microscope, EDX, ICP, TGA, and porosimeter.