• 한국통신학회논문지
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• 제11권1호
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• pp.25-39
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• 1986

본 논문에서는 packet switching network의 국제 표준 접속 protocol인 CCITT X.25 protocol의 성능을 분석하며 특히 X.25 protocol의 유통 제어 방식에 대하여 분석한다. Protocol의 성능 분석은 normalized channel throughput, mean transmission time과 transmission efficiency를 사용하면 이들은 window 크기, $T_1$ 및 $T_2$ 값 그리고 message길이 등과 같은 주어진 protocol parameter의 함수로 표시된다. 먼저 protocol 서비스에 따른 입력 데이타의 서비스 특성과 piggybacked acknowledgment를 하는 sliding window flow control 방식에 대하여 discrete-time Markov chain을 사용하여 연구한다. Protocol의 성능은 link layer 및 packet layer 에 대하여 각기 독립적으로 분석하며 분석결과를 통하여 각 protocol parameter의 영향을 조사한다. 수치적인 분석 결과로 부터 채널 서비스 환경에 따른 protocol parameter의 최적치를 찾을 수 있는데 window크기는 고속채널의 경우 7이상이 되는 것이 바람직 하며, $T_1$ timer 값은 채널의 전송 유실이 많은 경우 신중히 선택되어져야 하며 보통의 경우에는 1초 정도가 타당하다. $T_2$ parameter는 trnasmission efficiency의 개선에 있어 약간의 효과를 미치나 그리 크지는 않다.

• 대한교통학회지
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• 제26권4호
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• pp.63-76
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• 2008

본 연구는 교차로 지체를 고려한 통행시간함수를 개발하고, 이를 도시가로망에 적용하여 분석하는데 그 목적을 두고 있다. 이는 기존 통행배정 모형이 교차로 지체를 적절히 고려하지 못하고 있다는 분석에 근거하고 있다. 이를 위하여 본 연구에서는 링크의 통행시간을 구간 순행시간과 교차로 지체시간으로 구분하고, 청주시 주행속도, 교통량, 기하구조 및 신호운영 자료 등을 수집하여 계획단계에 적절한 구간 순행시간과 교차로 지체시간 산출모형을 구축하고, 이를 통행배정 단계에 적용하여 그 타당성을 분석하는데 중점을 두고 있다. 주요 연구결과는 다음과 같다. 첫째, 교차로 지체시간을 산출하기 위해 교차로의 녹색시간비 대신 접근로의 차로수비율을 교차로 유형별로 보정한 후, 이를 실제 녹색시간비율과의 t-검정을 시행하여, 평균값에 차이가 없다는 귀무가설을 기각할 수 없는 것으로 분석되어, 보정 차로수비율을 모형구축에 적용하였다. 둘째, 기존의 BPR모형과 보정 차로수비를 이용한 균일지체기반 수정모형 및 Webster기반 수정모형을 청주시 가로망에 EMME/2를 활용하여 통행배정하여 주행속도 조사자료와 비교한 결과, BPR모형은 교차로 지체의 영향을 반영하지 못하는 것으로 나타난 반면에 균일지체기반 수정모형과 Webster기반 수정모형은 관측된 조사자료에 보다 근접한 결과를 보였다. 셋째, 이들 모형의 배정결과와 실측 통행시간, 교통량, 평균통행속도간 통계검증 결과 통행시간 분리모형이 BPR모형 보다 실측치와의 통계적 오차가 감소하는 것으로 분석되었다.

• Asia pacific journal of information systems
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• 제20권1호
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• pp.33-56
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• 2010

The current business environment has been characterized as less munificent, highly uncertain and constantly evolving. In this environment, the company with dynamic capability is reported to be more successful than others in building competitive advantage. Dynamic capability focuses on the link between a dynamically changing environment, strategic agility, architectural reconfiguration, and value creation. Being characterized to be flexible and adaptive to market circumstance changes, an organization with dynamic capability is described to have high resource fluidity, which represents business process, resource allocation, human resource management and incentives that make business transformation faster and easier. Successful redeployment of the resources for dynamic adaptation requires organizational forms and reward systems to be well aligned with firm's technological infrastructures and business process. The alignment is considered to be an executive level commitment. Building dynamic capability is knowledge driven; relying on new knowledge to reconfigure firm's resources. Past studies established the link between the effective execution of a knowledge-focused strategy and relevant setting of architectural elements such as human resources, structure, process and information systems. They do not, however, describe in detail the underlying processes by which architectural elements are adjusted in coordinated manners to build knowledge-driven dynamic capability. In fact, understandings of these processes are one of the top issues in IT management. This study analyzed how a Korean corporation with a knowledge-focused strategy aligned its architectural elements to develop the dynamic capability and thus create value in the dynamically changing markets. When the Korean economy was in crisis, the company implemented a knowledge-focused strategy, restructured the organization's architecture by which human and knowledge resources are identified, structured, integrated and coordinated to identify and seize market opportunity. Specifically, the following architectural elements were reconfigured: human resource, decision rights, reward and evaluation systems, process, and IT infrastructure. As indicated by sales growth, the reconfiguration helped the company create value under an extremely turbulent environment. According to Ancona et al. (2001), depending on the types of lenses the organization uses, different types of architecture will emerge. For example, if an organization uses political lenses focusing on power, influence, and conflict. the architecture that leverage power and negotiate across multiple interest groups would emerge. Similarly, if an organization uses economic lenses focusing on the rational behavior of organizational actors making choices based on the costs and benefits of action, organizational architecture should be designed to motivate and provide incentives for the actors (Smith, 2001). Compared to this view, information processing perspectives consider architecture to be designed to maximize the capacity of information processing by the actors. Using knowledge lenses, the company studied in this research established architectural elements in a manner that allows the firm to effectively structure knowledge resources to form dynamic capability. This study is revelatory single case with a historic perspective. As a result of this study, a set of propositions and a framework are derived, which can be used for architectural alignment.

• 수산경영론집
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• 제14권2호
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• pp.15-68
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• 1983

From the economic point of view the fishing port is the complex of installations on land, organized to serve the fishing fleet and its cargo, and is the main link in the production chain of all components of the fishing industry, with the aim of achieving the planned targets with the minimum cost. Fishing port investment decisions have had significant impact on the development aims of Korean fisheries. Fishing port investments in Korea are made mostly by public or semipublic port authorities. Such investments should be judged not purely on the basis of financial profitability but rather on the extent to which they serve the development aims of the fishing industry. This makes the economic appraisal process more complex and presents certain problems in correctly quantifying the economic costs and benefits of the fishing port projects. This study concentrates more on the theoretical economic appraisal models than on the purely financial aspects of fishing port investments and points out the difference between the two approaches. In the result, there is clearly an element of judgment as to whether or not a shadow price needs to be used in estimating economic benefits and costs. From this viewpoint, some attempts are made to provide definitions of the possible economic benefits and costs, and methods for estimating and evaluating them in Part III and IV. Especially queueing theory is applied in the calculation of economic benefits. When a project is contemplated and analysis shows it to Lave a positive NPV, one question that arises is whether it should be implemented now or delayed. In this paper, the first year rate of return method is regarded as a more concise way of solving the timing of investment, At the end of Part IV, risk analysis of fishing port investments is considered. It can be handled in a number of ways, ranging from informal judgment to complex statistical analyses involving large-scale computer models, This paper recommends that evaluators of fishing port investments use the sensitivity analysis indicating exactly how much NPV will change in response to a given change in an input variable, other things held constant. Decisions regarding the amount of capacity to provide must be made in fishing port investments. Providing too much service would involve excessive capital costs. On the other hand, not providing enough service capacity would cause the waiting line of fishing vessels to become excessively long at times. Therefore, in Part V, the optimal number of berths and berth productivity in fishing port are defined as follows: Minimize E(TC) ＝ E(WC)＋E(SC) The minimum of this function is the solution and that is the optimal number of berth and berth productivity in fishing port.

• 한국수자원학회논문집
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• 제31권4호
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• pp.385-396
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• 1998

우리나라 서남부지역은 금강, 만경강, 동진강, 영산강 및 이들 하구 담수호와 관련하여 용수수급에 있어 불균형을 이루고 있는 실정이다. 예를 들면, 금강하구호는 저수용량이 작기 때문에 많은 양을 바다로 버리고 있는 실정이다. 반면, 현재 건설중인 새만금호는 비교적 저수용량에 비하여 유입량이 적은 편이다. 그리고 영광, 영암의 경우와 같이 영산강 하류 지역은 용수수요량은 많고 공급량은 부족한 실정이다. 이러한 용수수급의 불균형을 해결하고, 수자원의 이용 효율을 높이기 위해 다중저수지 연계운영모형(HOMMS : Hierarchical Operation Model for Multi-Reservoir System)을 개발하여 이들 담수호가 연결수로에 의해 서로 연결되었다고 가정하여 다중저수지 연계운영을 시도하였다. 그 결과 2011년을 목표로 기존의 담수호에서 약 21억 m3의 농어촌용수가 추가로 필요한 것으로 추정되었으며, 이 양은 각 담수호를 연계운영함으로서 무효방류량 19억 m3 을 물이 부족한 지역으로 도수가 가능하여 재사용할 수 있는 것으로 나타났다.

• KEPCO Journal on Electric Power and Energy
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• 제5권3호
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• pp.141-147
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• 2019

최근 전력산업에 가장 커다란 이슈는 신재생에너지의 증가이며 이에 따라 전력계통의 수용성을 확보하기 위한 다양한 기술개발이 추진되고 있다. 또한 세계적으로 보다 융통성 있는 친환경 에너지의 활용을 위하여 국가 및 지역간 전력계통을 연계하는 슈퍼그리드의 구성이 추진되고 있다. 이러한 성격이 서로 다른 계통 간에 연계를 위하여 반드시 요구되는 기술이 초고압 직류송전기술이다. 지금까지 국내에서는 육지와 제주도를 해저케이블로 연결하는 HVDC 송전기술이 적용되었으나 동해안의 발전단지에서 수도권의 부하밀집 지역으로 장거리 대용량 전력전송을 위한 직류가공송전 방식의 기술개발이 추진되고 있다. 인구밀도가 높고 산악이 많은 국내 환경을 고려해 최소한의 경과를 활용하여 8 GW 급의 대용량 전력을 전송하기 위해 도체귀로방식의 ${\pm}500kV$ Double Bipole 송전선로 설계기술을 개발하고 이를 적용하기 위한 사업화를 추진하고 있다. 본 논문에서는 세계 최초로 적용 예정인 도체귀로방식의 Double Bipole 송전선로의 설계를 위한 절연특성에 관한 연구를 수행하고 송전선로에 발생하는 다양한 과전압현상에 견디는 공기절연특성을 실증시험을 통하여 검증하고 이를 서술하였다.

• 한국통신학회논문지
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• 제32권7A호
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• pp.762-769
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• 2007

적응 전송 MIMO(multiple input multiple output)-OFDM(orthogonal frequency division multiplexing) 시스템은 CSI(channel state information)의 되먹임을 이용하여 각 부반송파의 채널 상황에 따라 변조 방식을 다르게 전송하는 시스템이다. CSI 되먹임 채널인 상향링크 채널에는 송수신기 처리지연, 전송 지연, 프레임 지연 등 다중 지연 요소가 존재한다. 이러한 다중 지연요소로 인한 CSI 불일치는 채널 상황에 따라 적절한 변조 방식을 결정하는데 오류를 발생시키게 되어 시스템 성능을 떨어트린다. 본 논문에서는 적응 시스템에 내장되는 다중 지연 채널 예측 방식인 CTSBP(comb type samples based prediction)와 BTSBP(block type samples based prediction)에 대해 전송 지연 및 채널 신호 대 잡음비에 따른 MSE (mean square error), 데이터 율 등 성능을 비교한다. 이를 통하여 악조건 다중경로 채널환경에 강건한 적응 전송 SISO(single input single output)-OFDM/MIMO-OFDM을 설계한다. 또한 CSI 되먹임 오버헤드를 줄이기 위한 방안으로 선형보간 방법을 제안하고 선형 보간 간격에 따른 MSE를 도출한다.

• 미술이론과 현장
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• 제16호
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• pp.257-272
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• 2013

This paper analyzes six different ways of articulating the relationship between art and politics. It calls attention to the differences that lurk behind the seemingly simple phrase-everywhere in vogue today-the "politics of aesthetics." Five of these models are drawn from contemporary discussions regarding the politics of art. The last model is the attempt to develop an account of the politics of aesthetics that is faithful to the difficult and ambiguous dimensions of the aesthetic experience that were hinted at by the texts of classical philosophical aesthetics. Most notably, this paper is concerned with the idea that the aesthetic experience can be understood as a form of disinterested contemplation-one that is not reducible to cognitive or moral considerations-and with some of the consequences that this entails. It explores some of the political significance that can be attributed to this idea of disinterested contemplation, arguing that the aesthetic should be understood as a withdrawal from the world's pre-established meanings. Unlike some of the other thinkers discussed in this paper, this author doubts that a single, uniform meaning can be ascribed to the aesthetic experience. I thus argue that we need to approach the aesthetic through the networks of textual significance that have been built up around it. Throughout this paper, I attempt to explain how the efforts to link art and aesthetics to politics simultaneously give rise to ideas about the nature of the human community. In looking at the sixth and final model, what I have called the "anarchical politics of aesthetic ambiguity," I argue that the aesthetic tradition offers a rather unique way of understanding the relationship between the individual and the community. Here, we see that the aesthetic is prone to a number of paradoxes, central among them the one that makes art the bearer of a solipsistic pleasure in which we nevertheless discover our capacity for genuinely communicating with others, outside of cliches and banalities.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.158-158
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• 2015

Myoblast are myogenic precursors that proliferate, activate, and differentiate on muscle injury to sustain the regenerative capacity of skeletal muscle; The neuronal isoform of nitric oxide synthase (nNOS, termed also NOS-I) is expressed in normal adult skeletal muscle, suggesting important functions for Nitric oxide (NO) in muscle biology1,2,3. However, the expression and subcellular localization of NO in muscle development and myoblast differentiation are largely unknown. In this study, we examined effects of the nitric oxide generated by a microwave plasma torch, on proliferation/differentiation of rat myoblastic L6 cells. Experimental data pertaining to nitric oxide production are presented in terms of the oxygen input in units of cubic centimetres per minute. The various levels of nitric oxide are observed depending on the flow rate of nitrogen gas, the ratio of oxygen gas, and the microwave power4. In order to evaluate the potential of nitric oxide as an activator of cell differentiation, we applied nitric oxide generated from the microwave plasma torch to L6 skeletal muscles. Differentiation of L6 cells into myotubes was significantly enhanced the differentiation after nitric oxide treatment. Nitric oxide treatment also increase the expression of myogenesis marker proteins and mRNA level, such as myogenin and myosin heavy chain (MHC), as well as cyclic guanosine monophosphate (cGMP), However during the myotube differentiation we found that NO activate oxidative stress signaling erks expression. Therefore, these results establish a role of NO and cGMP in regulating myoblast differentiation and elucidate their mechanism of action, providing a direct link with oxidative stress signalling, which is a key player in myogenesis. Based on these findings, nitric oxide generated by plasma can be used as a possible activator of cell differentiation and tissue regeneration.

• The Journal of Korean Physical Therapy
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• 제28권2호
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• pp.149-154
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• 2016

Purpose: The aim of this study is to suggest an intervention method for clinical use in the future by analyzing the effect of breathing exercise on activity of sternocleidomastoid muscle and scalenus anterior muscle, which are respiratory synergist muscles, and pulmonary functions in patients with forward head posture. Methods: Prior to the experiment, 12 patients (experimental group) performed feedback exhalation exercise along with conventional deep neck exercise, and 11 subjects (control group) performed feedback deep neck exercise along with conventional deep neck exercise. The intervention programs were performed for 40 minutes once a day (three times a week for four weeks). Results: Before intervention, %RMS was measured for surface electromyography (sEMG), and FVC, FEV1, and FEV1/FVC were measured using a spirometer. After four weeks, these items were re-measured under the same condition and analyzed. In within-group comparison of the experimental group, activity of sternocleidomastoid muscle and scalenus anterior muscle showed a significant decrease (p<0.05)(p<0.001), and forced vital capacity (FVC) showed a significant increase (p<0.05). In within-group comparison of the control group, activity of sternocleidomastoid muscle and scalenus anterior muscle showed a significant decrease (p<0.05), and in between-group comparison, there were significant differences in activity of sternocleidomastoid muscle and FVC (p<0.05). Conclusion: Long-term forward head posture restrains exercise performance of the neck and leads to exercise avoidance of the neck during daily activities, thus restraint factors might be created even while breathing. To cut off this link, a constant effort is required and diversified research on the correlation between neck functions and breathing should be conducted.