• Electronics and Telecommunications Trends
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• v.31 no.5
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• pp.120-130
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• 2016

21세기 디지털 사회에서는 각 개인의 연결과 상호작용이 사회 현상에 막대한 영향을 미치고 있으며, 이로 인해 사회는 더욱 복잡해지고, 순간적으로 급격한 변화가 일어나는 현상이 빈번히 발생한다. 사회 복잡성(Social Complexity)은 다수의 사회 구성원들 간의 복잡한 연결로 인해 발생하는 상호작용 패턴을 의미한다. 2011년 발생한 '아랍의 봄' 혁명, 글로벌 금융위기, 조류독감의 발생과 확산, 글로벌 기후 변화, 테러리스트들의 네트워크와 사이버 범죄의 증가 등은 복잡하게 연결된 글로벌 사회 현상으로 발생하는 복잡성의 사례들이다. 우리 사회의 안전성과 지속성을 확보하기 위해, 이러한 사회 복잡성을 그려내어, 그 속에 숨겨진 패턴을 분석하고 예측하는 기술에 대한 연구 개발이 국가적으로 필요하다. 다양한 분야의 사회적 모형을 개발하고 서로 연결하여, 복잡한 사회적 상호작용을 대규모 시뮬레이션을 통해 현상 분석과 사회경제 정책적 대응방향에 대한 통찰력을 가질 수 있는 대규모 '모사현실(Simulated Reality)' 기술 개발을 서둘러야 한다.

• Journal of Korean Home Economics Education Association
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• v.31 no.1
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• pp.39-58
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• 2019

The purpose of this study was to investigate the home economics pre-service teachers' verbal interactions during their teaching practicum. For this purpose, the class interactions of four pre-service teachers were recorded, and the data were analyzed using advanced Flanders' verbal interaction analysis. The major findings are as follows: First, the item with the highest proportion of occurrences consisted of the pre-service teachers' 'lectures', 'nonverbal conditions' and 'asks questions'. 'forms a positive learning atmosphere' and 'praises or encourages' exhibited fewer occurrences, and there was little 'giving direction', 'criticizing students or justifying authority'. Second, the instances of class interactions appeared in the form of 'asks questions-student talk response' or 'lecture-asks questions', and in the last class were 'ask questions-student talk initiation' and 'accepts or uses ideas of students'. Third, trends of verbal interactions tend to be generally indirect, and students' remarks have appeared acceptable and compassionate. Fourth, according to expert analysis, 'class management questions' and 'diffusion questions' have increased. Pre-service teachers can guide students through their learning activities, and students can expand their thinking through the teachers' questions. As these results demonstrate, self-study analyses of pre-service teachers and active support in field are needed.

• Journal of Korean Society for Geospatial Information Science
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• v.14 no.2 s.36
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• pp.77-88
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• 2006

Overpopulation has been one of the most serious problem of the Seoul Metropolitan Area (SMA), which consists of the City of Seoul, Incheon, and the whole of Gyeonggi Province. People have been still moving into SMA, especially being concentrated into the fringe of Seoul. This study examines the inner city decline phenomenon of SMA which can be easily found in large cities over the world, based on the demographic data of these area. In addition, this study monitors the imbalance in growing of SMA by analyzing RMI (Rank Mobility Index), and the inverse relation between the self sufficiency of the adjacent area and the commuting rate to Seoul by analyzing commuting data. Even though the total population has been unchanged, the internal change of population was substantial. The growth of Seoul Metro region was placed near the city of Seoul, especially commuter data reassured the population concentrations. The results will be useful in urban planning and growth management.

• Journal of Korea Technology Innovation Society
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• v.14 no.spc
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• pp.1256-1284
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• 2011

Although a existing consumer market have been studied in depth in the new technology product market, the market research on the overall level of value chain to consist of consumers, distributors, and manufacturers is weak. Therefore, in this paper consumers' purchase of new technology products were simulated and analyzed by a consumer selection model and a multi-agent model, which consist of consumers, distributors and manufacturers. Our research was focused on customer preference study in new technology product market by using conjoint analysis and discrete choice model. And changes in consumer behavior based on adoption of new technologies and offering of incentives were analyzed by ABM (Agent-based Model). In conclusion, the market share of technology products was risen when provision of incentives corresponding to inventory level and demand for new technology products occurred at the same time.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.3
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• pp.1-8
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• 2009

DS-CDMA system has very low bandwidth efficiency, hence it is difficult to maintain high spreading gain for high speed data transmission. Offset stacked spreading CDMA(OSS-CDMA) is a transmission scheme where spreading codes with chip offsets are overlapped, then transmitted. This kind of system requires a code set that guarantees orthogonality between codes in the set of any cjip offset. An orthogonal complementary code set has a property that the crosscorrelation function between codes in the group is zero for all shifts, hence it can be used for an OSS-CDMA system. In an OCC-OSS CDMA system each user is assigned an orthogonal complementary code group. User data bit is spread by the given codes and overlapped, and the code sequences are transmitted with multicarrier. However, the offset stacked spread sequences are multilevel, and the number of symbol levels is increases as the spreading efficiency is increased. When the OSS sequence is transmitted with MPSK mapping, the signal constellation becomes dense, and the system is easily affected by channel impairments. In this paper, we propose a level clipping scheme on OSS sequence before MPSK modulated. Simulations have been carried out to investigate the BER performance of the OCC-OSS CDMA system in AWGN environment. The results show that proposed scheme outperform the scheme without level clipping.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.4 no.4
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• pp.261-270
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• 1992

To investigate the flow patterns and diffusions in the Taean coastal waters of the eastern Yellow Sea, hydraulic and numerical experiments of tidal currents and diffusions of dye and cooling water were performed during spring tide along with field observations. Flow patterns obtained by the hydraulic and numerical experiments approximately coincide with those of the field observations. In the fold observations of tidal current, currents flow southwestward during the ebb tide, while currents flow northeastward during the flood tide. and the maximum velocity is 2.13 ㎧ toward WSW direction. The Eulerian diffusion coefficient estimated from field measmements of current is 7.82$\times$10$^{5}$ $\textrm{cm}^2$/s. Diffusion coefficients obtained from the area of dye plume in the model are given by the expression 0.18 $r^{4}$3/, and the coefficients have the range of 10$^{5}$ ~10$^{6}$ $\textrm{cm}^2$/s. These values are similar to the Eulerian diffusion coefficient estimated fram field measurements. Diffusion coefficients obtained in the hydraulic model are one to two orders higher than those obtained in the Onsan Bay in the eastern waters and two to three orders higher than those obtained in the Chinhae Bay in the southern waters of the Korean Peninsula. Diffusion patterns of cooling water by numerical experiments are similar to those of dye plume by hydraulic experiments. Both hydraulic and numerical experiment results of diffusions of dye plume and cooling water in the Taean coastal waters, have shown that the diffusion during the ebb tide is more prevalent than one during the flood tide.

• Information Systems Review
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• v.14 no.1
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• pp.21-35
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• 2012

The rapid growth and popularity of Twitter have been one of the most influential phenomena in the era of social network system and the mobile internet, which also opens up opportunities for new business strategies; in particular, PR and marketing area. This study analyzed use of Twitter in terms of user characteristics and message attributes. Actual field data from the Twitter for PR and Marketing of a representative Korean IT company (Company "K") was used for this analysis. Research findings show that overall corporate twitter users show passive attitude in retweet behavior. Also, users who have relatively small network size (less than 1,000) are more active in retweet than power twitterians that have big network size(over than 10,000). It is showed that the rate of retweet is higher in the order of recruiting, promotional event, IT information, and general PR message. In the conclusion section, practical implications based on the research finding are thoroughly discussed.

• Membrane Journal
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• v.12 no.4
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• pp.207-215
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• 2002

The hindered diffusion in confined spaces is an important phenomenon to understand in a micro-scale the filtration mechanism determined by the particle motion in membrane pores. Compared to the case of spherical colloids, both the theoretical investigations and the experiments on the hindered diffusion of polyelectrolytes is actually more difficult, due to lots of relevant parameters resulting from the complicated conformational properties of the polyelectrolyte chain. We have successfully performed the Brownian dynamics simulations upon a single polyeiectrolyte confined in a slit-like pore, where a coarse-grained bead-spring model incorporated with Debye-Huckel interaction is properly adopted. For the given sizes of both the polyelectrolyte and the pore width, the hindered diffusion coefficient decreases as the solution ionic concentration decreases. It is evident that a charge effect of the pore wall enhances the hindered diffusion of polyelectrolyte. Simulation results allow us to make sense of the diffusive transport through the micro-pore, which is restricted by the influences of the steric hindrance of polyelectrolytes as well as the electrostatic repulsion between the polyelectrolytes and pore wall.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.409-409
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• 2013

최근, 집적 소자의 미세화에 따라 늘어난 배선 신호 지연 및 상호 간섭, 그리고 소비 전력의 증가는 초고집적 소자 성능 개선에 한계를 가져온다. 이에 따라 기존의 알루미늄(Al)/실리콘 절연 산화막은 구리(Cu)/저유전율 박막(low-k)으로 대체되고 있고, 이는 소자 성능 개선에 큰 영향을 미친다. 그러나 Cu는 Si과 low-k 내부로 확산이 빠르게 일어나 소자의 비저항을 높이고, 누설 전류를 일으키는 등 소자의 성능을 저하시킬 수 있는 문제점을 가지고 있다. 이러한 Cu의 확산을 막기 위하여 Ta, TaN 등과 같은 확산방지막에 대한 연구가 활발히 진행되어 왔으나, 배선 공정의 집적화와 low-k 대체에 따른 공정 및 신뢰성 문제로 인해 새로운 확산방지막의 개발이 필요하게 되었다. 이를 위해, 본 연구에서는 Cu-V 합금을 사용하여 low-k 기판 위에 확산방지막을 자가 형성 시키는 공정에 대한 연구를 진행하였다. 다양한 low-k 기판에서 열처리조건에 따른 Cu-V 합금의 특성을 확인하기 위해 4-point probe를 통한 비저항 평가와 XRD (X-ray diffraction) 분석이 이뤄졌다. 또한, TEM (transmission electron microscope)을 이용하여 $300^{\circ}C$에서 1 시간 동안 열처리를 거쳐 자가형성된 V-based interlayer가 low-k와 Cu의 계면에서 균일하게 형성된 것을 확인하였다. 형성된 V-based interlayer의 barrier 특성을 평가하고자 Cu-V합금/low-k/Si 구조와 Cu/low-k/Si 구조의 leakage current를 비교 분석하였다. Cu/low-k/Si 구조는 비교적 낮은 온도에서 leakage current가 급격히 증가하는 양상을 보였으나, Cu-V 합금/low-k/Si 구조는 $550^{\circ}C$의 thermal stress 에서도 leakage current의 변화가 거의 없었다. 이러한 결과를 바탕으로 열처리를 통해 자가형성된 V-based interlayer의 Cu/low-k 간 확산방지막으로서 가능성을 검증하였다.

• Journal of Korea Society of Industrial Information Systems
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• v.26 no.5
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• pp.79-94
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• 2021

Despite the importance of the supply chain risk due to the negative word-of-mouth (NWOM) in social media, related research is insufficient. Thus, this study analyzes how the NWOM of the product is distributed through social media and the characteristics of the distributor based on social exchange theory. For this purpose, we collected information on car recalls from four companies using Twitter from the National Highway Traffic Safety Administration (NHTSA). Based on the Seed Tweet, a Re-Tweet (RT) network was constructed to examine the distribution and spread of NWOM, and regression analysis was performed to test the hypothesis. As a result, it was confirmed that NWOM is a small world network structure that spreads around hub users connected to many users. Moreover, it was found that the more interactive and reciprocal relations the first distributor has, the greater the speed and scale of distribution of NWOM.