• Proceedings of the KAIS Fall Conference
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• 2012.05a
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• pp.367-370
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• 2012

본 연구는 하나의 장치 내에서 "싸이클론-관성충돌-여과포 집진"이라는 다단 제진 단계가 동시에 이루어져 입경 분포별로 순차적인 제진이 가능한 멀티 집진기의 처리가스 제어 효율을 극대화시킬 수 있는 기류 흐름을 얻기 위한 최적화 설계 조건을 검토하는 것이다. 우선 1단계 제진 과정인 원심력을 이용하여 조대입자의 유선 이탈을 촉진시킬 수 있는 사이클론 유동을 최적화시키기 위한 집진기 입구 형상 설계 검토를 위해 수치 해석적 연구를 수행하였다. 그 결과, 멀티집진기 입구 형상을 일반적인 설계 방식인 접선 유입식으로만 설계한 것에 비해 선회류를 한번 더 가속화시킬 수 있는 가이드 베인을 추가로 설계한 경우 선회류의 pitch가 짧고 강하게 형성되어 사이클론부에서 조대입자의 유선 이탈을 촉진시키는데 매우 효과적인 것으로 예측되었다. 단, 사이클론부 하단 벤츄리 형상으로 인해 약 4~5 m/s의 강한 하향 흐름이 호퍼 하단까지 형성되고 있어 탈리 분진의 재비산 문제가 발생할 가능성이 크므로 벤츄리 형상 설치 유무에 대한 영향도 추가적으로 연구가 필요할 것으로 판단된다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.3 no.3
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• pp.154-160
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• 1970

The present paper deals with the growth of yellow croaker by scale age reading. This study is based on material from 596 specimens caught by the Danish seine in the Yellow Sea during the period from June 1967 to April 1968. Ring marks of the scale were formed from April to July, corresponding to the spawning season of the fish reported by Bae (1960). Growth rate of each radius of the ring was approximately 0.73. The relationship between the total length and radius of scales, and the relationship between the body weight and total length are represented by the following equations respectively: L=61.350R+50.184 $$W=4.298L^{3.227}\times10^{-3}$$ Maximum total length calculated by the diagram of Walford's growth transformation, $$L_{n+1}=0.6866L_n+10.8730$$, was 346.9mm. Growth curve of the fish can be expressed by the following von Bertalanffy's equation : $$L_t=346.9(1-e^{-0.376(t+0.609)})$$

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.3
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• pp.491-498
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• 2017

GPS (global positioning system) is a popular system that provides location information by measuring arrival time difference at the receiver between several GPS satellite signals. GPS is widely used in commercial area as well as military systems. Reliable GPS signal reception is more important in the military applications such as guided missiles. However, since the carrier frequencies of the GPS signals are well known and the received power is extremely low, the GPS systems are vulnerable to intentional jamming attacks. To remove jammers while maintaining GPS signals at the received signals, a popular technique is an adaptive beam steering method based on array antenna. Among adaptive beam steering techniques, this paper considers MVDR (minimum variance distortionless response) algorithm, and proposes a new adaptive technique that preserves the received signals at desired directions, but removes the unknown jamming signals adaptively. The performance of the proposed method is verified through computer simulation.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.145-150
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• 2005

A maximum of 3 km thickness of sediments were deposited above basement deformed by volcanic activities around the Dok Island. As the geological structure, the tension caused the basement-involved normal faults in the early stage of basin formation, whereas the sediment layers showed normal faults, volcanic domes and sills caused by volcanic activities. From the distribution of volcanics in order of age at the Ulleung Basin, volcanic activities were increased toward the northeastern direction (toward Dok Island). The study area is characterized by extensional crustal deformation before sediment deposition during the Early or Middle Miocene age, After the Late Miocene age, the basin was deformed by deep buried volcanics or subsidence of basin, in consequence, became complex geological structures.

• Korean journal of communication and information
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• v.38
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• pp.119-146
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• 2007

The purpose of this paper is to explore the factors causing adolescents' habitual use of text-based online social interaction (TOSI). The authors of the present study assumed that adolescents' perceived intimacy would affect the use of TOSI. Using structural equation modeling, the influences of perceived social presence and Internet self-efficacy on habitual use of TOSI were examined indirectly as well as directly, with and without intimacy as a mediate factor. The results show that the indirect effects were proven to be stronger compared with the direct effects. Perceived intimacy appeared to encourage more frequent uses of TOSI. The effects of intimacy were even more stronger especially with those who had higher levels of Internet self-efficacy.

• Korean journal of communication and information
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• v.42
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• pp.79-106
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• 2008

Based on the third-person effect hypothesis, this study conducted a nation-wide online survey to assess how Korean voters perceived the mass media's effect on the candidates' image and voting behavior during the 17th presidential election. The research results showed that the voters tended to perceive that the mass media such as newspaper, television and the Internet had a greater effect on others than on themselves with regards to the formation of the three candidates' images. The third-person effect on the voting behavior was also revealed differently in terms of the medium according to age and political tendency of the voters. For instance, the younger and liberal voters were likely to see newspaper as having a greater influence on other voters' choice of candidate, while the older voters saw TV as having a greater effect on other voters. The conservative tendency did not affect the perception of the voters at all. Another noteworthy result was that personal characteristics of the candidates' images such as appearances and communication skills did not affect the voters' behaviors in the election process.

• Journal of the Korean Geographical Society
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• v.32 no.2
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• pp.245-263
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• 1997

Housing market is segmented through 1) housing supply classified by housing characteristics and 2) housing demand classified by different housing opportunity of household. Moreover, neighborhood plays a role in intensifying housing market segmentation as a factor affecting on decision making relevant to housing supply and demand. while segmented housing markets have different mechanism, existing studies on residential differentiation and housing market have overlooked the characteristic differences among housing submarkets as the studies presume metropolitan housing market to be a single housing market. while the concept of 'residential differentiation' pays much attention on spatial pattern after the ecological approach appeared, the concept of ‘housing submarkets' is explanatory of the process of urban space structure formation. Analysis on housing submarkets makes up for the weak points of the behavioral approach inquiring into socio-economic constraint and different housing opportunity of household.

• Korean Chemical Engineering Research
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• v.53 no.1
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• pp.103-110
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• 2015

In this work, the performance of various promoters was investigated used in $CO_2$ separation from the gases emitted from steel-making process using gas hydrate technology. The studied promoters are tetrahydrofuran (THF), propylene oxide and 1,4-dioxane, which are all expected to form a structure II hydrate, and the target gases include $CO_2/N_2$ mixed gases ($CO_2/N_2$ = 20/80 and 40/60) and Blast Furnace Gas (BFG). The phase equilibrium points were measured when each promoter was added with various concentrations. For fast acquisition of abundant data, the "continuous" Quartz crystal microbalance (QCM) method was employed. In addition, the crystal structure of each gas hydrate was analyzed by Powder X-ray diffraction (PXRD).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.1
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• pp.33-40
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• 1989

In the design of reinforced concrete framed structures, which consist of various design variables, the objective and the constraint functions are formulated in complicated forms. Usually iterative methods have been used to optimize the design variables. In this paper, multilevel formulation is adopted, and design variables are selected in reduced numbers at each level, to reduce the iterative cycle and to accelerate the convergence rate. At level 1, elastic analysis is performed to get the upper and lower bounds of the redistributed design moments due to inelastic behavior of the frame. Then the design moments are taken as design variables and optimized at level 2, and the sizing variables are optimized at level 3. The optimization of redistributed moments is performed using the design sensitivity obtained at the level 2, and force approximation technique is used to reflect the variation of design variables in the lower level to the upper level. The design variables are selected in reduced numbers at each level, and the optimization formulation is simplified effectively. A cost function is taken as the objective function, and the constraints of the stress of the structures are derived from BSI CP 110 following limit state theory. Numerical examples are included to prove the effectiveness of the developed algorithm.

• Proceedings of the Korean Society of Community Living Science Conference
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• 2009.09a
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• pp.83-83
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• 2009

암을 제외한 대부분의 성인병은 혈액순환과 관련된 혈관계 질환들로 이들에 의한 사망 비율의 합은 암의 비율과 비슷하게 나타나 혈관계 질환의 심각성을 나타내고 있다. 혈전에 의한 혈관계 질환은 혈전용해제와 트롬빈저해제를 이용하여 치료하고 예방할 수 있으며, a-glucosidase 저해제는 당뇨병 예방과 치료에 이용할 수 있다. 예로부터 민간요법에서 다양하게 이용되어 왔던 반하를 성인병 치료와 예방에 관련된 기능성식품의 자료로 사용하기 위해 반하 열수추출물을 유기 용매로 분획화하고 분획물의 혈전용해활성, 트롬빈저해활성, 혈당강하효과를 측정하였다. 혈전을 직접 용해하는 활성을 측정하기위해 100 mg/ml의 농도로 준비한 시료액을 fibrin plate 방법을 이용하여 혈전용해활성을 측정 결과 hexane 층, chloroform 층, ethyl acetate 층, butanol 층에서는 활성을 나타내지 않았지만 물 층에서 만 0.8 plasmin unit의 높은 혈전용해활성을 나타냈다. 혈전의 형성을 억제하기위해 혈전형성의 필수 효소인 트롬빈의 활성을 저해하는 트롬빈저해활성을 측정하기위해 10 배 희석한 (10 mg/ml) 시료 용액을 이용하여 트롬빈저해활성을 측정결과 hexane 층에서 75.3%의 높은 트롬빈저해활성을 나타냈으며, ethyl acetate 층과 chloroform에서도 각각 43.3%와 39.7%의 활성을 나타냈다. 또한 탄수화물의 소화를 지연시킴으로서 소장에서 포도당의 흡수를 억제하여 혈관내 당의 농도를 조절하는 혈당강하제의 개발을 위해 준비된 조효소액(10 mg/ml)을 이용하여 a-glucosidase 저해활성을 측정한 결과 ethyl acetate 층과 hexane 층에서 각각 24.9%와 23.4%의 저해활성을 확인하였다. 따라서 반하의 hexane 층과 ethyl acetate 층과 물층은 혈전관련 혈관계 질환과 당뇨병 관련 기능성 식품의 개발 소재로 이용할 수 있을 것으로 기대된다. 특히 최근 질병 치료에 효과는 크지만 부작용이 동반되는 화학약품들 대신 활성은 조금 뒤지지만 부작용이 없는 생약을 이용하려는 경향이 커지고 있다. 따라서 오랫동안 민간용법에서 사용되고 있는 반하는 안정성이 확인된 장점을 갖고 있어, 식품재료나 기능성 음료에 이용할 경우 장기간 섭취가 가능해 혈관계 질환의 치료와 예방에 큰 효과를 가져 올 수 있을 것으로 기대된다.