• Asia pacific journal of information systems
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• 제20권1호
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• pp.127-140
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• 2010

The benefit that a consumer derives from the use of a good often depends on the number of other consumers purchasing the same goods or other compatible items. This property, which is known as network externality, is significant in many IT related industries. Over the past few decades, network externalities have been recognized in the context of physical networks such as the telephone and railroad industries. Today, as many products are provided as a form of system that consists of compatible components, the appreciation of network externality is becoming increasingly important. Network externalities have been extensively studied among economists who have been seeking to explain new phenomena resulting from rapid advancements in ICT (Information and Communication Technology). As a result of these efforts, a new body of theories for 'New Economy' has been proposed. The theoretical bottom-line argument of such theories is that technologies subject to network effects exhibit multiple equilibriums and will finally lock into a monopoly with one standard cornering the entire market. They emphasize that such "tippiness" is a typical characteristic in such networked markets, describing that multiple incompatible technologies rarely coexist and that the switch to a single, leading standard occurs suddenly. Moreover, it is argued that this standardization process is path dependent, and the ultimate outcome is unpredictable. With incomplete information about other actors' preferences, there can be excess inertia, as consumers only moderately favor the change, and hence are themselves insufficiently motivated to start the bandwagon rolling, but would get on it once it did start to roll. This startup problem can prevent the adoption of any standard at all, even if it is preferred by everyone. Conversely, excess momentum is another possible outcome, for example, if a sponsoring firm uses low prices during early periods of diffusion. The aim of this paper is to analyze the dynamics of the adoption process in markets exhibiting network effects by focusing on two factors; switching and agent heterogeneity. Switching is an important factor that should be considered in analyzing the adoption process. An agent's switching invokes switching by other adopters, which brings about a positive feedback process that can significantly complicate the adoption process. Agent heterogeneity also plays a important role in shaping the early development of the adoption process, which has a significant impact on the later development of the process. The effects of these two factors are analyzed by developing an agent-based simulation model. ABM is a computer-based simulation methodology that can offer many advantages over traditional analytical approaches. The model is designed such that agents have diverse preferences regarding technology and are allowed to switch their previous choice. The simulation results showed that the adoption processes in a market exhibiting networks effects are significantly affected by the distribution of agents and the occurrence of switching. In particular, it is found that both weak heterogeneity and strong network effects cause agents to start to switch early and this plays a role of expediting the emergence of 'lock-in.' When network effects are strong, agents are easily affected by changes in early market shares. This causes agents to switch earlier and in turn speeds up the market's tipping. The same effect is found in the case of highly homogeneous agents. When agents are highly homogeneous, the market starts to tip toward one technology rapidly, and its choice is not always consistent with the populations' initial inclination. Increased volatility and faster lock-in increase the possibility that the market will reach an unexpected outcome. The primary contribution of this study is the elucidation of the role of parameters characterizing the market in the development of the lock-in process, and identification of conditions where such unexpected outcomes happen.

• 지역연구
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• 제31권1호
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• pp.3-20
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• 2015

본 연구는 도시의 특정 기능이 도시규모에 의존하는지 혹은 도시 네트워크도에 의존하는지를 파악함으로서 네트워크 도시이론의 적용가능성을 검토하고자 하는데 주된 목적을 가지고 있다. 이를 위하여 본 연구에서는 2005년 및 2010년 전국 163개 시 군을 대상으로 실증분석을 수행하였다. 분석의 결과를 종합하면 다음과 같다. 규모기반은 제조업에 큰 영향을 미치는 것으로 나타났으며, 네트워크 기반은 주로 서비스업에 영향을 미치는 것으로 나타났다. 또한 시기의 흐름에 따라, 규모기반이 미치는 영향은 과거에 비해 점차 감소하는 반면, 네트워크기반이 미치는 영향은 서비스업을 중심으로 점차 증대되는 경향이 있음을 확인할 수 있었다. 본 연구에서는 새로운 시대의 담론으로서의 네트워크 도시이론의 적용 가능성을 실증적으로 분석하였다는 측면에서 그 의의를 갖는다고 할 수 있겠다.

• 한국지역사회생활과학회지
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• 제25권4호
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• pp.511-531
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• 2014

This study explores supportive and conflictual network structures of elderly single and couple households and analyzes the effects of supportive and conflictual networks on suicidal thoughts by gender and family type. The analysis considered a sample of 522 individuals over the age of 60 who did not live with their adult children. The statistical methods used to analyze data were descriptive statistics, a t-test, a chi-square test and a regression analysis using SPSS WIN 20.0. The results are as follows. First, men and elderly single households had support networks that were smaller than those of women and elderly couple households. The conflictual network of elderly couples households was larger than that of elderly single households. In addition, the larger the network, the more the conflictual was. Second, elderly single households thought about suicide more often than elderly couple households. Third, economic status, the number of adult children, the size of conflictual network and subjective health had considerable influence on suicidal thoughts of elderly single and couple households. The size of the conflictual network had a greater effect on suicidal thoughts of elderly individuals than that of the supportive network. These results have important policy implications for elderly single and couple households.

• 산업경영시스템학회지
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• 제42권2호
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• pp.1-8
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• 2019

Network externalities are essentially dynamic in that the value consumers feel about a product is affected by the size of the existing customer base that uses that product. However, existing studies on network externalities analyzed the effects of network externalities in a static way, not dynamic. In this study, unlike previous studies, the impact of network externalities on price competition in a vertically differentiated market is dynamically analyzed. To this end, a two-period duopoly game model was used to reflect the dynamic aspects of network externalities. Based on the game model, the Nash equilibria for price, sales volume, and revenue were derived and numerically analyzed. The results can be summarized as follows. First, if high-end product has strong market power, the high-end product vendor takes almost all benefits of the network externality. Second, when high-end product has strong market power, the low-end product will take over most of the initial sales volume increase. Third, when market power of high-end product is not strong, it can be seen that the effects of network externalities on the high and low-end products are generally proportional to the difference in quality. Lastly, if there exists a strong network externality, it is shown that the presence of low-end product can be more profitable for high-end product vendor. In other words, high-end product vendor has incentive to disclose some technologies for the market entrance of low-end product, even if it has exclusive rights to the technologies. In that case, however, it is shown that the difference in quality should be maintained significantly.

• 산학경영연구
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• 제19권2호
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• pp.183-206
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• 2006

최근 네트워크 효과가 존재하는 산업에서 "승자의 이익 전유"와 "기술적 고착화"는 일반적 현상으로 인식되고 있다. 이러한 산업에서는, 하나의 기술이 한 번 앞서면 그 기술이 시장 전체를 지배하도록 만드는 수익체증이 존재한다는 것이다. 이는 실무적인 면에서, 초기의 산업진입을 통한 고객기반의 선점이 기업들에게 지속적으로 초과이윤을 창출할 수 있는 시장지배력을 제공해 줄 수 있다는 매력적인 시사점을 제공한다. 그러나 현실의 산업변화 과정을 살펴보면, 기존의 지배적 기술이 새로운 기술에 의해 대체된 경우가 오히려 더 많으며 기술혁신은 끊임없이 일어나고 있음을 제시하고 있다. 본 연구는 네트워크 효과가 존재하고 기술진보가 빠른 산업에서 기업들 간의 기술혁신경쟁을 분석함으로써, 이러한 산업에서 동태적 경쟁우위를 확보하기 위한 기업들의 기술선택문제에 대한 다음과 같은 시사점을 도출하였다. (1) 신기술의 기존기술과의 비호환적인 경우 보다는 호환적인 경우에, 산업은 신기술로 진화할 가능성이 크다. 따라서 기존기업이 성능이 우수한 신기술을 활용하지 않는다면, 수익 기반을 상실할 가능성이 높다. (2) 신기술이 기존기술과 비호환적인 경우, 산업의 진화방향은 전문사용자의 비중과 신기술의 출현 시기에 따라 결정된다. 전문사용자의 비중이 낮을수록, 신기술의 출현시기가 늦을수록, 기존기술을 활용하는 기업들에게 유리하게 산업이 진화함으로써 하나의 기술에 고착화된다. 반면에, 전문사용자의 비중이 높을수록, 신기술의 출현시기가 빠를수록, 산업의 진화는 새로운 기술을 탐색하고 이를 과감히 활용하는 기업들에게 유리하게 전개된다.

• 한국발생생물학회지:발생과생식
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• 제16권4호
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• pp.265-270
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• 2012

Ethanol actions in the amygdala formation may underlie in part the reinforcing effects of ethanol consumption. Previously a physiological phenomenon in the basolateral amygdala (BLA) that is dependent on neuronal network activity, compound postsynaptic potentials (cPSPs) were characterized. Effects of acute ethanol application on the frequency of cPSPs were subsequently investigated. Whole cell patch clamp recordings were performed from identified projection neurons in a rat brain slice preparation containing the amygdala formation. Acute ethanol exposure had complex effects on cPSP frequency, with both increases and decreases dependent on concentration, duration of exposure and age of the animal. Ethanol produces complex biphasic effects on synaptically-driven network activity in the BLA. These findings may relate to subjective effects of ethanol on arousal and anxiolysis in humans.

• 한국정보통신학회논문지
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• 제13권2호
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• pp.215-220
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• 2009

IEEE 802.15.4로 알려진 LR-WPAN(Low-Rate Wireless Personal Area Network)은 현재까지 발표된 시스템 규격 중에서 가장 USN(Ubiquitous Sensor Network)을 구현하기 적합한 시스템으로 인식되고 있다. 본 논문에서는 LR-WPAN이 900MHz 대역에서 이용되는 경우, 타 시스템에 미치는 간섭 영향을 시뮬레이션하였다. 국내의 900MHz 대역 주파수 이용 현황을 고려해보면, LR-WPAN이 RFID/USN으로 할당된 주파수를 공유해서 이용하는 것을 생각해볼 수 있다. LR-WPAN이 RFID/USN 대역을 공동으로 이용하는 경우에 대한 간섭 시뮬레이션 결과, CT1과 RFID에 미치는 간섭 확률은 각각 2.5%와 2.1%로 계산되었으며, 공공통신에 미치는 간섭영향이 없기 위해서는 약 100m 이상의 보호거리가 필요한 것으로 계산되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제32권4호
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• pp.508-518
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• 2019

Objective: This research aimed to determine biological pathways and protein-protein interaction (PPI) networks for 305-d milk yield (MY), 305-d fat yield (FY), and age at first calving (AFC) in the Thai multibreed dairy population. Methods: Genotypic information contained 75,776 imputed and actual single nucleotide polymorphisms (SNP) from 2,661 animals. Single-step genomic best linear unbiased predictions were utilized to estimate SNP genetic variances for MY, FY, and AFC. Fixed effects included herd-year-season, breed regression and heterosis regression effects. Random effects were animal additive genetic and residual. Individual SNP explaining at least 0.001% of the genetic variance for each trait were used to identify nearby genes in the National Center for Biotechnology Information database. Pathway enrichment analysis was performed. The PPI of genes were identified and visualized of the PPI network. Results: Identified genes were involved in 16 enriched pathways related to MY, FY, and AFC. Most genes had two or more connections with other genes in the PPI network. Genes associated with MY, FY, and AFC based on the biological pathways and PPI were primarily involved in cellular processes. The percent of the genetic variance explained by genes in enriched pathways (303) was 2.63% for MY, 2.59% for FY, and 2.49% for AFC. Genes in the PPI network (265) explained 2.28% of the genetic variance for MY, 2.26% for FY, and 2.12% for AFC. Conclusion: These sets of SNP associated with genes in the set enriched pathways and the PPI network could be used as genomic selection targets in the Thai multibreed dairy population. This study should be continued both in this and other populations subject to a variety of environmental conditions because predicted SNP values will likely differ across populations subject to different environmental conditions and changes over time.

• Journal of Information Technology Applications and Management
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• 제22권3호
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• pp.129-141
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• 2015

The purpose of this study is to provide an explanation for the association between the characteristics of a network and the type of innovation by considering the effect of absorptive capacity. To do so, this study examined the moderating effects of absorptive capacity on the characteristics of network-innovation relationship in a technical-driven venture company. In order to obtain a better understanding about consequences caused by interfirm network, information was obtained from 169 Korean IT venture companies. Results confirmed that the network diversity is positively associated with exploration. Our results also suggested that the network strength is positively associated with exploitation. Finally, we found a positive two-way interaction between absorptive capacity and the network diversity-exploration relationship. Then, we discussed implications and directions for future research.

• 한국생활과학회지
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• 제21권5호
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• pp.929-945
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• 2012

This study examined structured social network types and their relationship to quality on life satisfaction of older adults. Respondents were 418 adults aged 60 or older living alone or as couples. The data was analyzed using K-means cluster analysis. Four networks types were identified: diverse, friend-neighbor focused, family focused, and restricted. Life satisfaction was highest for individuals in the diverse network group and lowest for individuals in the restricted network group. Stepwise multiple regression analysis indicated that life satisfaction of the elderly was affected by the diverse network, family focused network, the relationship quality with children, the relationship quality with neighbors, and the relationship quality with relatives. Results suggested that having diverse social network in close proximity is very important in old age and structural network types may have important practical implications for improving the quality of life among the elderly.