• Science of Emotion and Sensibility
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• v.21 no.4
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• pp.25-36
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• 2018

Nowadays, it is hard to imagine one's life without smart phones or the internet. Furthermore, not only do people form groups offline, but also online. Based on the cognitive dissonance theory, there have been many studies about how an offline group's initiation affects attitudes toward the group. However, there has not been a study about how an online group's initiation can affect attitudes toward the group. Therefore, this study aims to find out how cognitive dissonance aroused by initiation affects the attitudes toward the online community, which represents groups that are formed online. In addition, this study examined how perceived similarity affects changes in attitude aroused by cognitive dissonance. Participants were assigned to a group in three ways as follows: without a registration process, with a simple registration process, and/or with a complex registration process. Perceived similarity was calculated by the difference between the current body mass index (BMI) and the target BMI of the participant. Attitudes toward the online group were measured by perceived source credibility, perceived information quality, satisfaction, information usefulness, and continuance intention. Contrary to the cognitive dissonance theory, the results showed that when applied to offline social groups, there were conflicting results. There were cases where there was no difference in the evaluation between initiation conditions. However, other cases showed that groups with the most complex registration process were found to have the worst evaluation. People were more favorable toward the group when the perceived similarity was larger. Interestingly, people who had higher perceived similarity had more positive attitudes toward the groups that had been assigned with a registration process compared to the group formed without a registration process. Conversely, people with lower perceived similarity had more positive attitudes toward the group when there was no initiation process. Online communities may use the results of this study to design more suitable registration processes for their communities.

• Journal of Internet Computing and Services
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• v.14 no.5
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• pp.1-10
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• 2013

RFID(Radio Frequency Identification) system is non-contact identification technology. A basic RFID system consists of a reader, and a set of tags. RFID tags can be divided into active and passive tags. Active tags with power source allows their own operation execution and passive tags are small and low-cost. So passive tags are more suitable for distribution industry than active tags. A reader processes the information receiving from tags. RFID system achieves a fast identification of multiple tags using radio frequency. RFID systems has been applied into a variety of fields such as distribution, logistics, transportation, inventory management, access control, finance and etc. To encourage the introduction of RFID systems, several problems (price, size, power consumption, security) should be resolved. In this paper, we proposed an algorithm to significantly alleviate the collision problem caused by simultaneous responses of multiple tags. In the RFID systems, in anti-collision schemes, there are three methods: probabilistic, deterministic, and hybrid. In this paper, we introduce ALOHA-based protocol as a probabilistic method, and Tree-based protocol as a deterministic one. In Aloha-based protocols, time is divided into multiple slots. Tags randomly select their own IDs and transmit it. But Aloha-based protocol cannot guarantee that all tags are identified because they are probabilistic methods. In contrast, Tree-based protocols guarantee that a reader identifies all tags within the transmission range of the reader. In Tree-based protocols, a reader sends a query, and tags respond it with their own IDs. When a reader sends a query and two or more tags respond, a collision occurs. Then the reader makes and sends a new query. Frequent collisions make the identification performance degrade. Therefore, to identify tags quickly, it is necessary to reduce collisions efficiently. Each RFID tag has an ID of 96bit EPC(Electronic Product Code). The tags in a company or manufacturer have similar tag IDs with the same prefix. Unnecessary collisions occur while identifying multiple tags using Query Tree protocol. It results in growth of query-responses and idle time, which the identification time significantly increases. To solve this problem, Collision Tree protocol and M-ary Query Tree protocol have been proposed. However, in Collision Tree protocol and Query Tree protocol, only one bit is identified during one query-response. And, when similar tag IDs exist, M-ary Query Tree Protocol generates unnecessary query-responses. In this paper, we propose Adaptive M-ary Query Tree protocol that improves the identification performance using m-bit recognition, collision information of tag IDs, and prediction technique. We compare our proposed scheme with other Tree-based protocols under the same conditions. We show that our proposed scheme outperforms others in terms of identification time and identification efficiency.

• Water for future
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• v.24 no.3
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• pp.49-60
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• 1991

As a second part of the study entitled "Field Measurement and Analysis of Fluvial Sediment in the Cheongmi-Strea", this study concerns mineralogical and contaminative characteristics of sediment particles collected at Wonbu-Gyo and Hanpyeong-Gyo in the Cheongmi-Stream. The mineralogical analysis of the bed sediment collected reveals that, in general , quarz is the most abundant mineral found in sands with feldspars and rock fragments in the next, which confirms what is known in the literature. The shape factor of sand particles is about 0.7, which also agrees to what is known in the foreign literature. The analysis also reveals that the clay particles collected are composed mainly of illite, kaolinate, and chlorite. The analysis of contamination reveals that there is no substantial difference between the contents of organic material and heavy metals in the surface water and those in the pore water beneath the river bed. It is because the sampling for this analysis was conducted right after the September flood during which the fresh top soil from the upstream watershed replaced the old bed sediment and pore water that would probably be more contaminated. The contents of geavy metals in the bed sediment of sand particles do not exceed those in the soils adjacent to the river. For fine sediment such as clays, however, the contents of heavy metals, especially of mercury and zinc, far exceed those in the soils adjacent to the river. These fine sediments are transported downstream in the form of wash load and deposited in part on flood plains, which could be a new source of contaminants.taminants.

• Journal of Nutrition and Health
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• v.34 no.6
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• pp.656-663
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• 2001

This study was carried out to evaluate the minerals and trace elements contents in colostrum milk produced from 30 normal healthy mothers delivery at term, 10 mothers delivery preterm and 8 pregnancy induced hypertensive mothers(PIH) and to investigate the relationship between maternal minerals intakes during pregnancy and milk contents of minerals. Five minerals(Na, K, Ca, P, Mg) and three trace elements(Fe, Zn, Cu) in colostrum were determined by ICP-AES and maternal dietary intakes during pregnancy were estimated by semiquantitative frequency questionnaire. Maternal dietary intakes of three groups during pregnancy were below the recommended allowances except protein and phosphorus. The overall mean nutrients intakes of mothers delivered preterm were the lowest among three study groups, especially phosphorus and sodium intakes of preterm mothers were significantly lower than those of normal term mothers(p < 0.05). Dietary intakes of mothers with pregnancy induced hypertension were similar to those of normal term mothers except calcium intake of pregnancy induced hypefensive mother was the lowest among three groups. While potassium and phosphorus concentrations in preterm colosalm were significantly lower than those of term milk(p < 0.05), iron contents of colostrum in preterm and PIH groups were significantly higher than term milk respectively(p < 0.07). The other minerals concentrations of colostrum produced by the preterm mothers tended to be lower than term milk. There were not significant relationships between maternal dietary intakes of minerals during pregnancy and the corresponding mineral levels of colostrum of three groups of mothers except that Pearson correlation coefficient showed positive significant relationships between the calcium intakes of PIH mothers and the colostrum milk calcium levels. These results suggest that preterm milk might be insufficient for the mineral nutrition of preterm infects in considering of the poor tissue storage of minerals and catch-up growth of preterm infects.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.56.1-56.1
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• 2010

결정질 실리콘 태양전지의 표면 ARC(Anti-reflection Coating)layer는 반사도를 줄여 광 흡수율을 증가시키고, passivation 효과를 통하여 표면 재결합을 감소 시켜 태양전지의 효율을 높이는 중요한 역할을 한다. Silicon nitride 박막은 외부 stress 요인에 대해 안정성을 담보할 수 있어야한다. 따라서, 본 연구에서는 굴절률 가변에 따른 silicon nitride 박막을 PECVD를 이용하여 증착하고, 항온/항습 stability test를 통해 박막의 안정성을 확인하였다. Silicon nitride 증착을 위해 PECVD를 이용하였고, 공정압력 0.8Torr, 증착온도 $450^{\circ}C$, 증착파워 300W에서 실험을 진행하였다 박막의 굴절률은 1.9~2.3의 범위로 가변하였다. 항온/항습에 대한 신뢰성을 test 하기 위하여 5시간동안의 test를 1cycle로 하여 20회 동안 실험을 실시하였다. 증착된 silicon nitride 박막의 lifetime은 firing 이후 57.8us로 가장 높았으며, 항온/항습 test 이후에도 유사한 경향을 확인 할 수 있었다. 또한, 100h 동안의 항온/항습 test 결과 silicon nitride 박막의 lifetme 감소는 8.5%에 불과했다. 본 연구를 통하여 온도와 습도의 변화에 따른 결정질 실리콘 태양전지의 SiNx 박막의 증착 공정 조건에 대한 신뢰성을 확인 할 수 있었다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.42.2-42.2
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• 2009

인체의 치아 및 뼈는 무기질 성분과 단백질로 구성되어 있다. 생체세라믹스의 일종인 수산화아파타이트(Hydroxyapatite, HA; $Ca_{10}(PO_4)_6(OH)_2$)는 결정학적, 화학적으로뼈의 무기질 성분과 거의 유사하여 실제 체내에 들어가면 주위 뼈와 화학적 반응을 하여 단단한 결합을 이루는 생체활성(bioactive)을 가진 것으로 알려져 있다. 또한, 인산삼칼슘(Tri-Calcium Phosphate, TCP; $Ca_3(PO_4)_2$)은 체내에 이식 시 체액에 용해되어 신생골을 유도하는 생체흡수성(bioresorbable) 세라믹스로 알려져 있다. 상기 2종류를 포함한 인산칼슘계 화합물은 우수한 생체친화성에도 불구하고 역학 특성이 낮아, 하중을 거의 받지 않는 분야에만 사용되고 있는 실정이며, 하중을받는 분야(load-bearing part)에 적용하기 위해서는 고강도/고인성의 세라믹스와의 micro-composite이나 인산칼슘계화합물을 금속 표면에 코팅한 macro-composite의 형태로 사용되고 있다. 하중을 거의 받지 않는 분야, 예를 들어 치아 결손부를 보충할 dental shot과 같은 인산칼슘계 다공질 골충전재의 경우에도 취급 시 잘게 파손되는 문제점이 있어 치과의사들이 어려움을 호소하고 있는 실정이다. 본 연구에서는 HA, TCP의 역학특성을 증진시키고자 소결 공정 제어를 통하여 미세조직을 변화시켰으며, 미세조직 변화에 따른 세포반응성을 골포세포주를 이용하여 평가하였다.

• Annual Conference on Human and Language Technology
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• 1997.10a
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• pp.271-276
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• 1997

대화체는 문어체와는 달리 화자와 청자 사이의 질의/응답으로 이루어진 형태의 문장들을 가지며, 생략과 대용어가 빈번히 발생하는 특징을 갖는다. 이러한 대화 형태에서 어떠한 한 문장에는 화자가 전달하고자 하는 의도를 포함하고 있다. 이러한 대화체 문장들을 번역하는 것은 단순한 언어적 분석에 의한 번역으로서는 많은 번역상의 오류가 발생하게 된다. 따라서 대화체 문장들의 올바른 번역을 위해서는 대화의 상황을 반영하는 문맥 정보가 부가적으로 요구된다. 본 연구에서는 이러한 문맥 정보로서 화행을 사용하여 대화체 기계번역을 수행하고자 한다. 화행(Speech Act)이란 화자에 의해 의도되어 발화 속에 포함된 언어적 행위를 나타내며, 이러한 화행을 분석함으로써 화자의 의도를 파악하고 이를 통해 올바른 번역을 수행할 수 있게 된다. 본 기계번역 시스템에 포함된 화행 분석 과정에서는 대화를 화행으로 모델링한 담화 문법과 유사한 형태의 재귀적 대화 전이망(Recursive Dialog Transition Network)을 사용하게 된다. 본 논문에서는 호텔 예약 영역에서의 기계번역 시스템에 대한 간단한 소개와 화행의 종류 및 분석 방법과 이를 통한 기계번역 방식에 대해 살펴보도록 하겠다.

• Korean Journal of Animal Reproduction
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• v.19 no.3
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• pp.205-216
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• 1995

Microtubules와 micrfilaments는 포유동물 난자이 주요한 세포 구조물들로, 이들은 난자의 성숙, 수정 및 배발달시 핵질의 이동과 세포질 분열에 직접 관여하는 것으로 알려져 왔다. 난자내 세포구조물의 정확한 움직임은 정상적인 배 발달을 위해 필수적이다. Microtubules는 $\alpha$, $\beta$- bubulin이 서로 연결되어 이루어져 있으며, 수정시 웅성.자성전핵 움직임과 세포분열시, 유사 및 감수분열시 그 역할을 한다. 생쥐를 제외한 대부분의 동물에서 microbubules의 역할은 수정시 정자가 centrosome을 난자내로 이전하여 sperm aster를 형성함으로써 시작된다고 보고되고 있다. 따라서 정자의 도움없이 배발달이 일어나는 단위발생시 microbubules의 형성은 연구들 사이에 흥미로운 연구대상이 되고 있다. 한편 microfilaments는 세포분열시 세포질을 분할하는 기계적인 역할을 하는 것으로 알려져 있으며, 최근 생쥐 난자에서는 정자의 난자내 융합과 웅성 및 자성 전핵의 이동에 관여한다고 보고되고 있다. 포유동물 난자의 체외성숙, 체외수정을 유도할 때 여러 가지 비정상적인 핵움직임과 세포분열이 관찰되어지고, 낮은 배발달율이 보고되고 있는데, 최근 연구자들은 세포구조물, 즉 microtubules와 microfilaments의 비정상적인 역할에서 기인한다고 보고 있다. 따라서 포유동물 난자의 성숙.수정 및 단위발생시 세포구조물의 움직임과 역할 및 상호관계에 대한 정확한 이해는 체외수정율 및 배발달 향상에 중요한 기초자료로 이용되리라고 본다.

• Journal of KIISE:Databases
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• v.27 no.2
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• pp.199-208
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• 2000

The k-nearest neighbor search query based on similarity is very important for content-based multimedia information retrieval(MIR). The conventional exact k-nearest neighbor search algorithm is not efficient for the MIR application because multimedia data should be represented as high dimensional feature vectors. Thus, an approximate k-nearest neighbor search algorithm is required for the MIR applications because the performance increase may outweigh the drawback of receiving approximate results. For this, we propose a new approximate k-nearest neighbor search algorithm for high dimensional data. In addition, the comparison of the conventional algorithm with our approximate k-nearest neighbor search algorithm is performed in terms of retrieval performance. Results show that our algorithm is more efficient than the conventional ones.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.951-956
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• 2010

본 연구에서는 $\bigcirc\bigcirc$화력발전소 회사장에 매립되고 있는 혼합회가 도로성토 및 철도노반 등 성토재로 사용될 수 있는가를 평가하기 위하여 물리적 및 역학적 특성을 평가하였다. 비중, 액소성 시험, 입도분석, XRD 시험, 강열감량시험, 실내투수시험을 통해 물리적 특성을 평가하였고 다짐시험, CBR 시험, 배수삼축압축시험을 실시하여 역학적 특성을 평가하였다. 두 가지 혼합회에 실험한 결과 비중은 2.181~2.189, 투수계수는 $1.32{\times}10^{-4}{\sim}1.89{\times}10^{-4}cm/sec$, 수정CBR은 19.5~21%, 배수마찰각은 $36.43{\sim}41.39^{\circ}$로 평가 되었다. 혼합회의 투수계수는 실트질 흙과 유사한 범위에 있으며 배수마찰각은 상대밀도가 큰 모래질 흙이 보일 수 있는 내부마찰각의 범위를 보였다. 본 연구에서 사용한 혼합회는 도로성토 및 철도노반 등 성토재로 사용할 수 있는 것으로 평가되었다.