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        검색결과 127

        1.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to determine the efficiency of the distribution process of the abalone industry, that is, whether there is market dominance. In addition, it was intended to find out whether there is an asymmetric price transfer phenomenon between the distribution stage of the abalone industry. The results of this study are summarized as follows. First, the asymmetric price transition effect on the abalone price between producer and wholesale market was found to be positive. It means that the distribution structure is incomplete between the producer and the wholesale market and the abalone market is operating inefficiently. Second, as a result of estimating the market power between the producer and the wholesale market, the market power coefficient between the producer and the Hanam wholesale market, and the producer and the Incheon wholesale market were 0.0618 and 0.0735. Summarizing the analysis results, the abalone market has an asymmetric price transition between producer and wholesale markets, but the market dominance coefficient is relatively low. These results suggest that the asymmetry of price transition is mainly caused by market dominance, but can also be caused by other factors such as information asymmetry. In the future, in addition to the market dominance of the abalone market, it is judged that research on factors related to the asymmetry of price transition is necessary.
        4,900원
        2.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we propose an optimal design method by applying the Prefabricated Buckling Restrained Brace (PF-BRB) to structures with asymmetrically rigidity plan. As a result of the PF-BRB optimal design of a structure with an asymmetrically rigidity plan, it can be seen that the reduction effect of dynamic response is greater in the case of arrangement considering the asymmetric distribution of stiffness (Asym) than in the case of arrangement in the form of a symmetric distribution (Sym), especially It was confirmed that at an eccentricity rate of 20%, the total amount of reinforced PF-BRBs was also small. As a result of analyzing the dynamic response characteristics according to the change in eccentricity of the asymmetrically rigidity plan, the distribution of the reinforced PF-BRB showed that the larger the eccentricity, the greater the amount of damper distribution around the eccentric position. Additionally, when comparing the analysis models with an eccentricity rate of 20% and an eccentricity rate of 12%, the response reduction ratio of the 20% eccentricity rate was found to be large.
        4,000원
        3.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 너클 라인이 다수 존재하면서 안팎 형상이 비대칭으로 설계된 특이점을 갖는 쌍동선의 자항성능을 예측하기 위 해 CFD 해석을 수행하였고, 해석 기법에 따른 차이를 파악하기 위해 MRF(Moving Reference Frame) 기법과 SDM(Sliding Mesh) 기법을 적용하 였다. MRF 기법을 적용한 경우에는 time step당 프로펠러를 1˚ 회전시켰고, SDM 기법의 경우 10˚, 5˚, 1˚씩 회전시키며 각 기법별 예측된 자 항성능을 비교하였다. 자항점 추정을 위한 몇 가지 프로펠러 회전수에서의 해석 결과 중 프로펠러의 토크는 기법에 따른 차이가 거의 없었 지만 추력 및 선체가 받는 저항은 MRF 기법보다는 SDM 기법을 적용했을 때 더 낮게, SDM 기법의 time step당 프로펠러 회전각이 작을수 록 높게 계산되었다. 선형 내삽을 통해 추정된 자항점의 프로펠러 회전수, 추력, 토크와 실선 확장법을 사용해 추정된 실선의 전달동력, 반 류 계수, 추력 감소 계수 및 프로펠러 회전수도 동일한 경향을 보였으며, 대부분의 자항효율은 반대의 경향을 보였다. 프로펠러 후류의 경 우 MRF 기법을 적용했을 때 정확도가 떨어졌고, SDM 기법의 time step당 프로펠러 회전각에 따라 표현되는 후류의 차이는 거의 없었다.
        4,000원
        4.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        해상풍은 대기-해양의 상호작용을 이해하는데 중요한 요소일 뿐만 아니라, 해양에서 기인하는 위험기상을 예측하는데 중요한 입력자료이다. 정확한 예측을 위해서는 정확한 해상풍 자료가 요구되지만, 육상과 달리 해상은 관측이 제한적이기 때문에 관측 자료가 많 지 않은 실정이다. 따라서 본 연구에서는 장기간의 고해상도 해상풍 자료 구축을 목표로 하였다. 먼저 장기간에 대해 활용 가능한 ERA5 재분석 바람장을 고해상도로 재격자화 하였고, 재격자화 한 ERA5 바람장을 수치모형 ADCIRC (ADvanced CIRCulation model)의 GAHM (Generalized Asymmetric Holland Model)을 이용하여 산출한 비대칭형 태풍 바람장과 합성하였다. 산출된 비대칭형 태풍 합성 바람장은 기상 청 (Korea Meteorological Administration, KMA) 및 일본 기상청 (Japan Meteorological Administration, JMA) 관측자료를 이용하여 정확도를 평가 하였다. 평가결과, ERA5 바람장 및 Holland 식을 이용하여 산출한 대칭형 태풍 합성 바람장보다 비대칭형 태풍 합성 바람장이 관측값을 매우 유사하게 재현하는 것으로 나타났다. 본 연구에서 생산한 해상풍 자료는 향후 폭풍해일 후측 자료 구축, 폭풍해일고 빈도 분석, 해상 풍 빈도 분석 등 다양한 연구의 기초자료로 유용하게 활용될 것으로 기대된다.
        4,000원
        5.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구는 한국의 유가증권시장과 코스닥시장의 비금융업종 기업을 대상으로 기업의 비대칭적 환노출과 기업의 주가급락위험 간의 관계를 분석하였다. 분석 기간은 2009년부터 2021년까지이다. 분석 결과 환율이 상승하는 경우 주가가 크게 하락하는 특성의 비대칭적 환노출이 있는 기업의 경우 주가급락위험이 감소하는 결과를 확인하 였다. 이러한 결과는 환율이 상승하는 경우 기업의 주가가 하락하는 정도가, 환율이 하락하는 경우 주가가 상승 하는 정도보다 큰 것으로 시장에서 확인되어 있는 경우 경영자는 환율 상승과 주가 하락에 관련된 정보를 은닉하기 보다는 환노출을 관리하는 선택을 하게 되고, 시장에서도 이러한 기업들의 환율변동과 주가 간의 관계에 관심을 갖게 되어 환율변동의 영향이 신속하게 주가에 반영되기 때문에 주가급락위험이 오히려 감소하는, 비대칭적 환노출 의 주가급락위험 감소 효과가 나타나기 때문인 것으로 판단된다. 그러나 평균적인 관계와는 달리 비대칭 환노출이 있는 기업의 경우 환율 상승에 따른 주가급락위험 증가의 가능성이 있음도 확인할 수 있었다. 이 연구의 분석 결과 는 환노출이 있는 기업의 경우 환노출과 관련된 정보를 시장에 충분히 공지하는 것이 주가급락위험 예방의 차원 에서 중요할 수 있음을 확인시켜 준다.
        6,300원
        7.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this research, a new structure of an asymmetric piston dedicated machining center is developed. By applying 2 linear motors in this machine, the slide unit structure could be simplified by comparing to the ball screw method, resulting in easier maintenance of the machine and enabling simultaneous machining in 2 axes and high-speed precision machining. In addition, a dedicated HMI for the asymmetric piston is developed to support efficient operation by workers, allowing them to verify product quality and take necessary actions. It is confirmed that by fully utilizing control libraries and productive programming languages, immediate response to future demands could be achieved. Through speed control loop performance testing, it is confirmed that applying feedforward function could improve the response speed, control accuracy, and stability of the speed control loop. The application of polynomial interpolation and Newton interpolation in the actual machining of asymmetric pistons confirmed the achievement of dynamic machining precision at high speeds. The developed machine and HMI are expected to contribute significantly to the efficiency, productivity, and improvement of product quality in the machining of asymmetric pistons.
        4,000원
        9.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A timber lattice roof, which has around 30m span, was constructed. In order to figure out the realistic buckling load level, the structural analysis of this roof structure was performed especially by stiffness of connection with various asymmetric snow load. Due to the characteristics of application of snow load, the load combinations of snow should be considered not only global area but also local part so that the critical buckling load could be observed as easy as possible. Geometrical imperfection was simulated to consider inaccurate shape of structure. And then nonlinear analysis were performed. Finally, this paper could investigate that the asymmetric snow load with the lower level stiffness of connection decreased the level of buckling load significantly.
        4,000원
        10.
        2022.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A microfluidic pump is a key component to controllably actuate fluids in Lab on a chip devices. To overcome technical issues of a diaphragm-type pump, a valveless nozzle-diffuser type pump was developed by utilizing the different flow resistance to control a dominant flow direction by means of diaphragm actuation. In this work, based on the operating mechanism of the nozzle-diffuser type pump, we propose a new concept of a valveless pump which can generate asymmetric flow through a pump chamber. In the proposed valveless pump, asymmetric flow path structures play a role of a nozzle-diffuser installed to a pump chamber. To validate the concept of the proposed valveless pump, we conducted CFD simulations for different geometries of the flow path structures. Based on the CFD simulations, we found that the dominant flow direction can be selectively manipulated by the pump actuation and an optimal shape of the asymmetric flow path structure was proposed to maximize the net mass flow rate through the pump chamber.
        4,000원
        13.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Most of the predictions using machine learning are neutral predictions considering the symmetrical situation where the predicted value is not smaller or larger than the actual value. However, in some situations, asymmetric prediction such as over-prediction or under-prediction may be better than neutral prediction, and it can induce better judgment by providing various predictions to decision makers. A method called Asymmetric Twin Support Vector Regression (ATSVR) using TSVR(Twin Support Vector Regression), which has a fast calculation time, was proposed by controlling the asymmetry of the upper and lower widths of the ε-tube and the asymmetry of the penalty with two parameters. In addition, by applying the existing GSVQR and the proposed ATSVR, prediction using the prediction propensities of over-prediction, under-prediction, and neutral prediction was performed. When two parameters were used for both GSVQR and ATSVR, it was possible to predict according to the prediction propensity, and ATSVR was found to be more than twice as fast in terms of calculation time. On the other hand, in terms of accuracy, there was no significant difference between ATSVR and GSVQR, but it was found that GSVQR reflected the prediction propensity better than ATSVR when checking the figures. The accuracy of under-prediction or over-prediction was lower than that of neutral prediction. It seems that using both parameters rather than using one of the two parameters (p_1,p_2) increases the change in the prediction tendency. However, depending on the situation, it may be better to use only one of the two parameters.
        4,300원
        14.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Poly(vinylidene fluoride) (PVDF) 막은 내구성 및 열적⋅화학적 안정성 등의 물성은 우수하나 소수성이 커서 수투과도가 낮고 단백질 및 유기물에 의한 막오염이 쉽게 발생한다. 본 연구에서는 PVDF 막의 내오염성을 개선시키고자 바이오 기능성 물질인 β-cyclodextrin (β-CD)을 PVDF 막 구조 내에 분산 함침시킨 PVDF/β-CD 혼합기질 비대칭막을 상변환 법을 통해 제조하고, β-CD 함침량에 따른 순수 투과 유속(PWF) 측정과 BSA 용액을 대상으로 한 막여과 실험을 수행하여 내오염성 특성을 평가하였다. 이 결과 PVDF 고분자 매질 내에 β-CD를 함침시키면 막의 친수성을 증가시켜 접촉각을 감소시키고 이로 인해 내오염성을 향상시킬 수 있었다. β-CD 함침량이 2 wt%인 도프용액을 사용하여 제조된 PVDF/β-CD 혼합 기질 비대칭막의 PWF는 64 L/m2⋅h, BSA 배제도는 95%를 나타내었으며, β-CD를 첨가하지 않고 제조된 pristine PVDF 막에 비해 투과 유속 향상성이 최대 80%에 달해 β-CD를 첨가시킴으로서 PVDF 막의 내오염성을 증가시킬 수 있었다.
        4,000원
        15.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 사장교 주탑의 심미성이 강조되고 있기 때문에 유한요소해석을 통해 안전성을 확보하여야 한다. 콘크리트 주탑은 케이블의 장력으로 인해 균열이 발생할 가능성이 높기 때문에 균열을 감소시키고, 구조적 안전성에 대한 계획이 필수적이다. 이 연구에서는 사장교 콘크리트 주탑의 균열제어 방법을 제시하고 유한요소해석을 통해 구조적 안전성을 검증하였다. 균열 위치는 사전해석을 통해 검토하였고, 적절한 균열제어방법이 제안되었다. 또한, 구조해석을 통해 보강 후 주탑의 안전성을 확인하였다.
        4,000원
        16.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study aims to investigate the factors that affect the practical condition of the convergence and convergence behaviors of the asymmetric transportation equilibrium problem (ATEP). METHODS : To achieve this objective, a real network experiment is critical because the crux of the problem associated with the ATEP is the difficulty of verifying the unique condition in real networks owing to asymmetric modeling. The study employed a numerical approach to deal with this problem because analytical derivation based on small networks has a limitation in extending its findings to practical applications. The study addressed the problems using large real networks and different types of interactions, including links and modes. An investigation of the factors that have the potential to affect the convergence of the problem was conducted with the solution algorithm, which is the double projection method. RESULTS : The study presented a partial answer to the question of whether the ATEP's convergence condition is too strong. In link interactions, demand intensities and symmetric features within the cost function along with the network configuration were determined to relax the convergence condition. In mode interactions, the degree of overlap of the route composition and the controlled asymmetric interactions in the cost function were determined to affect the convergence condition. CONCLUSIONS : The results suggested that the modeling of link interactions for a more complicated transportation system design enabled the modeling of complex asymmetric interactions as long as the demand intensity of the network was not strong. In the case of mode interactions, whereas it was not possible to control the route composition, it was considered possible to a degree where the use of a distinct route was observed for each class (for example, designated truck lanes).
        4,600원
        17.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Chlorhexidine is a cationic bisbiguanide with broad antibacterial activity, and diverse activity encompassing gram-positive and gram-negative bacteria, yeasts, dermatophytes, and some lipophilic viruses. Chlorhexidine alters the permeability of the bacterial membrane. They also neutralize periodontal pathogens such as Streptococcus aureus, Porphyromonas gingivalis, and Prevotella intermedia. Porphyromonas gingivalis were cultured to isolate the Porphyromonas gingivalis outer membranes (OPG). Also, OPG were used to prepare large unilamellar liposomes with total lipids (OPGTL) extracted and prepared with the phospholipids mixture (PL). The effect of chlorhexidine digluconate on cell membrane kinetic changes was investigated using fluorescence polarization of n-(9-anthroyloxy) stearic acid with different rotational mobility depending on the probe substitution position (n) in the membrane phospholipid aliphatic chain. Chlorhexidine digluconate increased the hydrocarbon rotational mobility interior of the OPG, OPGTL and PL, but native and model membranes interfacial mobility were decreased. The sensitivity to increasing chlorhexidine digluconate effect on rotational mobility was proportional to the depth of probe position in descending order of 16-AP, 12-AS, 6-AS and 9-AS. Chlorhexidine digluconate disordering or ordering the effects on the membrane lipids may cause its bacteriostatic and bacteriocidal actions.
        4,000원
        18.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본논문에서는 FTA 국내보완대책의 일환으로 추진되고 있는 폐업지원제도의 정부실패 사례를 살펴보고 그 원인을 규명하였으며, 더 나아가 이를 개선하기 위한 방안을 제시하였다. 1. 폐업지원제도는 FTA 이행에 따른 시장개방과정에 국내 농업의 경쟁력 제고와 농가 소득안정을 목적으로 정부가 동원한 정책수단의 하나임. 그러나 제도 운영과정에서 정부실패 사례가 나타남. 2. 폐업과정에서 신규 농가가 진입하여 정책효과가 저감되고, 예상보다 많은 농가가 폐업함으로써 해당 산업의 가치사슬이 왜곡되고, 폐업 후 타 작목으로 전환하면서 풍선효과가 나타나 간접피해를 유발하고, 생산규모가 자연적으로 감소하는 가운데 인위적인 폐업지원으로 비효율적 예산 투입이 이루어지고, 지원금 단가가 높아 과도한 폐원을 유도함. 3. 이와 같은 정부실패의 주요 원인은 정책 이해관계자 사이의 정보비대칭과 정보 부족임. 결국, 폐업지원제도의 운영과 정에서 나타난 정부실패를 해소하고 제도의 효과를 높이기 위해서는 제도 이해관계자 사이의 정보비대칭 혹은 정보 부족문 제를 해소해야 함. 4. 구체적인 대안으로 생산·가격·소득정보에 대한 이해관계자의 접근성을 높임과 동시에 사후 컨설팅사업 병행, 수입피해를 소명한 농가에 한해 지원하는 ‘신청주의’ 도입 등이 필요함.
        4,300원
        20.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this paper is to empirically investigate whether asymmetric price transmission exists in the distribution stage of farmed olive flounder market. For the analysis, time series data were used for the producer prices of Jeju and Wando, and the wholesale prices of Incheon, Hanam and Busan. Through the Granger causality test, the causal relationship from the producer price to the wholesale price was derived and the asymmetric price transmission was analyzed using the autoregressive distributed lag model (ARDL). As a result of the analysis, it was found that there is a phenomenon of ‘positive asymmetric price transmission’ from the producer price to the wholesale price. This result can be one evidence that excess profits are received in the intermediate distribution stage, and can be said to be a result showing the incompleteness and inefficiency of the distribution structure of the farmed olive flounder. In the future, it is required to establish an information-sharing system in all stages of production, distribution, and consumption that can create a competitive environment for distribution participants and resolve information asymmetry. Also, it is necessary to review the distribution center specializing in live fish from the viewpoint of the establishment of new distribution channels and sales diversification strategy under the rapidly changing fisheries environment.
        4,800원
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