• The Korean Journal of Applied Statistics
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• v.30 no.3
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• pp.475-486
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• 2017

This paper estimates the health life expectancies for Korean people based on a sample cohort database collected through objective measurements by the National Health Insurance Service. Health life expectancy is estimated using the single-state approach of Sullivan (1971). The 9-order correction factor method of Greville (1945) and Brass-logit model of Brass (1971) are also adopted for unobserved or incompletely observed age-specific morbidity and mortality. Based on the mortality and morbidity estimated from sample cohort DB, men and women in Korea are expected to live a 'healthy life' for 61 and 60 years in 2013, respectively, whereas life expectancies of men and women are 80 and 87, respectively. We also estimate certain disease-free life expectancies for each of genders, income levels, and types of insurance from 2003 to 2013 in Korea. We found that there exists an inequality of healthy life expectancy in Korea for different genders, income levels, and types of insurance.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.3
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• pp.262-271
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• 2000

This study was carried out to clarify the spatial and temporal patterns of benthic environments and macrobenthos on the subtidal soft-bottom in Chonsu Bay. Seasonal surface water temperature was similar to the bottom layer, but freshwater discharges into the outlets dereased the surface salinity around the dyke in summer. Bottom dissolved oxygen was decreased deeply around the dyke and created the de-oxygenated layer during summer. Sediment grain size was consisted of finer at the neighboring of the dyke than the mouth of the bay. Organic matters including the sediment were decreased at the mouth of the bay. A total of 311 species ($769\;ind./m^2$) were identified. Polychaetes were the most abundant faunal group in the number of species and densities. The number of species revealed the spatial patterns that it was higher in the mouth of the bay, and their densities showed seasonal changes by mass recruitment occurred at the most of the area in summer, At this time, opportunistic species, Lumbrineris iongifolia and Theora fragilis, were also recruited massively. Chonsu Bay were classified into five station groups by the cluster analysis. The dominant species around the dyke were composed to opportunistic species, those in middle area were Sternaspis scutata, Paraplionospio pinnata, and those in the mouth of the bay were Mediomastus californiensis, Nephtys polybranchia. Seasonal fluctuations and spatial difference of environments seem to have influenced to the species compositions and affected to the stability of benthic ecosystems spatial-temporally In Chonsu nay.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.117-124
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• 2015

Purpose: The purpose of this study was to compare the accommodative function of young adult in their 20s wearing monovision, modified monovision, and aspheric multifocal contact lenses at near task. Methods: Thirty young adults ($23.53{\pm}2.37years$) were fitted with monovision, modified monovision (the application of single vision contact lenses and center-near low addition aspheric multifocal contact lenses), and aspheric center-near multifocal contact lenses. After wearing these modalities during a week for adaption, and after watching visual display at computer for inducing accommodative pressure for 1 hour. The following assessments of accommodative function were made: contrast visual acuity (VA) at distance and near; accommodative response; near accommodative facility; and negative relative accommodation (NRA)/positive relative accommodation (PRA). All measurements were carried out binocularly. Results: In binocular distance VA with contrast of 10%, monovision was the worst among the four modalities (p=0.005). In accommodative response at 1 m (1.00 D), monovision was the lowest (p<0.05) and accommodative response at 40 cm (2.50 D) with monovision was lower than that of modified monovision and multifocal contact lens (p<0.05). We also found that there were no significant differences in accommodative facility and NRA/PRA among the four modalities. Conclusions: In young adult (20s), monovision with low add reduced the accommodative response at near task, however, modified monovision and multifocal lens with center-near type did not affect accommodative relaxation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.5B
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• pp.385-394
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• 2012

The tactical mobile communication network, which comprises a part of the next-generation Tactical Information and Communication Network (TICN), provides means of communication and control for Tactical Multi-Functional Terminals (TMFT) belonging to a Mobile Subscriber Access Point (MSAP). The next-generation of MSAP is capable of constructing a backbone network via LCTR and HCTR directional antennas. At the same time, WMN modules are used to create and manage a wireless mesh backbone. When directional antennas are used in mobile environments, seamless services cannot be efficiently supported as the movement of the node prevents the angle of the antenna to constantly match. Therefore, data communication through the wireless mesh networks is required to provide direct communication between mobile MSAPs. Accordingly, mutual authentication and data encryption mechanisms are required to provide reliable data transmission in this environment. To provide efficient mutual authentication between MSAP devices, the process of verifying a certificate of the other MSAP device through its own authentication server is required. This paper proposes mutual authentication mechanisms where the MSAP requiring authentication and the MSAP that permits it initiates low-cost and efficient authentication in a distributed way. More specifically, we propose a method of applying EAP-ELS (Extensible Authentication Protocol-Transport Layer Security) in the next-generation TICN.

• Information Systems Review
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• v.21 no.3
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• pp.63-86
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• 2019

As the use of ICT became a part of daily social life, online community has emerged as a new type of social organization. Online community is a virtual space which enables many people to participate and contribute together to collective knowledge. Anonymity in online communities can encourage active social participation by people with various social constraints, however, anonymity can also lead to serious social pathology. As a result, it is necessary to study on what is fundamentally influencing human behavior and how people's behavior is controlled in anonymous online community. This study focuses on human identity and investigate the factors affecting human behavior control in anonymous online environment by examining various aspects of identity in online discussion community. This study empirically verifies the causal relationship between factors, including social & technical anonymities, various identity dimensions, intrinsic motivation to participate in the community, group norm conformity, and quality of discussion. It also analyzes the difference between groups by the level of anonymity, gender, age, community usage period, and discussion topic. Based on the findings, this research provides theoretical and practical implications for online community management strategies and a better culture on Internet discussion.

• International Commerce and Information Review
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• v.13 no.3
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• pp.489-510
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• 2011

Free Trade Agreement (FTA) between the Korea, of the one part, and the EU and its member states, of the other part, has been effective, as of 1 Jul 2011. EU enlarged its members up to 27 countries including Romania and Bulgaria in 2007, and stood up as the second largest trading partner to the Korea right after the China. FTA, generally, shows the several different figures according to the countries concerned on the agreement The EU has long history and cultural, educational assets. In addition to that, the EU also has economical, industrial bases. Therefore, the EU seeks fruitful profits utilizing its intellectual property rights. There are copyrights and related rights, trade marks, geographical indications, designs, and patents, etc. on the Chapter 10. intellectual property rights of the Korea EU FTA. Among them, the others except geographical indications seem to be somewhat the terms advantageous to the Korea. It is possible to ask further requirements to the Korea in the years to come because the EU member countries are very much interested in the practical profits of intellectual property rights. Thus, it would be essential tasks for us to review the intellectual property rights protection and features of the Korea EU FTA.

• The Korean Journal of Financial Management
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• v.27 no.2
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• pp.63-84
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• 2010

We investigate whether FX hedging materially increases firm value by testing the valuation effect of Foreign Exchange Risk Insurance in Korea, using our sample of 84 listed firms with 617 observations between 2000 and 2008, Employing Tobin's Q as a proxy of firm value and foreign exchange risk insurance as a proxy of hedging instrument, we find a positive relation between firm value and the use of foreign exchange risk insurance. The hedging premium is statistically significant and is on average 7.4% of sample firm value. We also find our empirical results consistent with the preceding evidence that firm uses the hedging instrument in order to alleviate economic frictions and then hedging causes an increase in firm value.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.553-564
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• 2017

We analyzed the effects of government intervention on competition structure of telecommunication companies.. Results showed a decrease in market share difference among mobile telecommunication companies due to increased competition caused by the introduction of mobile virtual network operators (MVNO) and mobile number portability. We also found that the introduction of the MVNO caused a relaxed competition structure between network operators. Furthermore, we observed an increased subscriber influx of late adapters after the introduction of the Mobile and Service Retail Regulation Law (MRL). However, we found a gradual decrease in the competitiveness of MVNO following the introduction of MRL. In addition, the introduction of Mobile and Service Retail Regulation Law had a negative impact on customer churn as well as the financial structures of telecommunication companies.

• Information and Communications Magazine
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• v.11 no.2
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• pp.77-89
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• 1994

High speed optical fiber transmission technology has been remarkably improved during the past 20 years. This paper presents recent research status and future technological issues for the future information society, that is, the Tb/s transmission by frequency division multiplexing and the ultra long-distance by optical soliton transmission. Erbium-doped fiber amplifier and recent optical technology have brought optical transmission system of up to 10 Gb/s to the point of commercialization. Taking into account the future super information highway, that is, B-ISDN network, ultra wide-band picture-based information can be provided for many subscribers via existing optical fiber cables. However, to achieve the high speed transmission, the technologies must be developed not only for transmission lines but also for transmission nodes. Since the conventional signal transmission/processing technique using electronics has the limit in its speed, novel photonic technology is being developed for this purpose. On the other hand, optical solitons propagate stably through optical fibers, without pulse broadening effect of the fiber dispersion. Since the pulse broadening effect becomes serious as the transmission speed increases, optical solitons is the important technologies to realize the high speed, long distance transmission.

• 한국HCI학회:학술대회논문집
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• 2006.02b
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• pp.770-779
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• 2006

한국 사회에서 사이버 공간, 특히 온라인 게임 세계가 사용자들에게 단순한 게임이나 가상 공간이 아닌 다양한 활동을 통해 현실과는 다른 방식의 또 다른 인생을 살아가는 새로운 생활공간으로 기능하고 있다. 본 연구에서는 온라인 게임 공간에서의 라이프스타일 유형을 확인하고, 리니지 2 와 메이플스 토리라는 두 가지 MMORPG 게임에서 이 유형이 어떻게 나타나는지를 확인하였다. 온라인 게임 '리니지'에서 구분된 온라인 라이프스타일은 '싱글 플레이어', '공동체지향 게이머', '탈사회적 게이머'였다.'리니지 2'를 대상으로 연구 결과, 온라인 게임 공간에서의 공동체 활동은 크게 공동목표, 집단유대감, 집단존중감, 집단영향력의 요인들로 구성되어있는 것으로 확인되었다. 온라인게임 사용자들은 온라인 게임에서 현실감, 조작용이성, 성취감, 친밀감, 소속감, 일탈적 행위를 통한 카타르시스를 통해 재미를 느끼는 것으로 확인되었다. 하지만, 이런 성향은 메이플스토리라는 저 연령층의 게임에서는 비교적 다르게 나타났다. 혈맹 또는 길드의 가입 비율은 비슷한 수준이었지만, 활동방식은 라이프스타일에 따라 다르게 나타났다. 게임세계에서의 라이프스타일은 연령이나 게임 사용기간에서는 큰 차이가 없는 것으로 나타났다. 그러나 공동체 활동과 온라인 게임에서 얻는 재미의 하위 요인들에서는 분명한 차이가 있는 것으로 확인되었다. 공동체 활동과 재미를 느끼는 측면에서의 차이로 인해 결국 온라인 게임에 몰입하는 정도도 차이가 있는 것으로 나타났다. 본 연구는 사이버 공간에서의 사람들의 심리적, 행동적 특성, 특히 온라인 게임에서의 사람들의 공동체 활동과 재미의 요소들을 탐색하였다는 측면에서 의의가 있다. 사람들이 온라인 게임 세계에 몰입하도록 만드는 요인들을 구체적으로 확인할 수 있었다는 측면에서 향후 사이버 공간을 기획하는 사람들에게 구체적인 시사점을 제시할 것이다.