• Journal of Information Technology Applications and Management
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• 제29권3호
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• pp.25-41
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• 2022

While there exists voluminous literature on the internationalization of the firms, it has focused on mature firms or born-global firms. There is still a lack of research on firm that is in the growth stage between venture and mature firm. To fill this gap, this paper focuses on the newly public firm which is enter the stock market through initial public offerings (IPO). Specifically, I examine the relationship between the early listing and internationalization. In the venture firm aspect, the decision of the IPO necessary to allow to change organization structure, ownership and take a risk from environmental movements. This paper suggests early listing is a behavior of entrepreneur orientation. According to empirical results, there is a positive relationship between early listing and internationalization. It implies that early listing may help international expansion by sourcing finance, reputations from market. Furthermore, this study emphasizes the importance of financial slack resources to international expansion. I conclude that ventures need not only early entering in stock market but also securing sufficient financial slack resources to achieve sustainable growth in the international market.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.314-314
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• 2000

This study deals with the analysis of the effectiveness of a safer belt in frontal crash. ATB, Articulated Total Body, program is used as a dynamics solver of the occupant model. ATB is a public code, however, the program is somewhat cumbersome to use due to lack of sufficient user interface. A preprocessor and a postprocessor are, therefore, developed for a user friendly graphic interface in Windows environment. Dialog boxes are used for an interface with GEBOD, Generator of Body Data, for human anthropometry and with ADAMS for vehicle dynamics. It is found through three test simulations that simulated results are in good agreement with those obtained by ATB. The effect of the initial slack of safety belt is investigated for frontal crash using the developed program.

• 전자공학회논문지
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• 제54권7호
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• pp.21-28
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• 2017

FPGA 배치 툴 연구는 학계에서도 단순한 가상 아키텍처 모델 가정에서 벗어나 상용 툴처럼 캐리체인이나 광폭함수 멀티플렉서, 메모리/승산기 블록 등의 성능 및 밀도를 향상시키는 소자들을 포함하는 현실적인 모델을 적용하기 시작하였다. 이 때 발생하는 실제적 이슈들을 다룬 사전 패킹, 다층 밀도 분석 등의 기법이 초기 분석적 배치 (Analytic Placement)에 적용되어 밀도를 분산시키면서 배선 길이를 효과적으로 최소화한 연구가 앞서 발표된 바 있다. 더 나아가 궁극적으로는 타이밍을 최적화해야하기 때문에 많은 연구에서는 타이밍 제약 조건을 만족시키기 위한 기법들이 제시되고 있다. 그러나 초기 배치 후 진행되는 배치 적법화 및 배치 개선에서 주로 적용될 뿐 분석적 배치에서 이러한 타이밍 기법을 적용한 사례는 거의 없다. 본 논문에서는 사전 패킹 및 다층 밀도 분석 등의 기법이 구현된 기존 분석적 배치에 타이밍 제약 조건 위반을 검출하고 이를 최소화하는 기법을 결합하는 방안을 소개한다. 먼저 정적 타이밍 검증기를 집적하여 배선 길이가 최소화된 기존 배치 결과의 타이밍을 검사해 보았으며 위반을 감소시키기 위해 신호 도착 시간 (Arrival Time)을 최소화하는 함수를 분석적 배치의 목적 함수에 추가하였다. 이 때 각 클록마다 주기가 다를 수 있기 때문에 각 클록별로 함수를 따로 계산해 합산하는 방안이 제안되었다. 또한, 위반이 없는 클록 도메인의 신호 경로들도 불필요하게 단축될 수 있기 때문에 음수 슬랙 (Negative Slack)을 계산하여 이를 최소화하는 함수를 추가로 제안하여 비교하였다. 영역 분할 기법 (Partitioning)을 기반으로 배선 길이를 최소화하는 기존 배치 적법화를 그대로 사용한 후 타이밍 검증을 통해 초기 분석적 배치 단계에서 타이밍 개선 효과를 분석하였다. 배치 적법화 시 추가적인 타이밍 최적화 기법이 사용되지 않았기 때문에 타이밍 개선이 있다면 이것은 전적으로 분석적 배치의 목적 함수개선에 의한 효과이다. 12개 실용예제에 대해 실험한 결과, 목적 함수에 도착 시간 함수가 적용되었을 때 그렇지 않았을 때보다 최악 음수 슬랙 (Worst Negative Slack)이 평균 약 15% 정도 감소되었으며 음수 슬랙 함수가 적용되었을 때 이보다 약 6%정도 추가로 더 감소됨을 확인하였다.

• 한국안전학회지
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• 제32권3호
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• pp.117-122
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• 2017

In this study, we studied the ride quality considering the deterioration effects of the three type couplers (single, double, and ring types) for EMUs. In order to know the impact occurred when an urban transit vehicle is under breaking, we tested the conditions of the service brake and the emergency brake. Normal coupler models without any slack showed similar dynamic performance results under all breaking conditions. But if the couplers become old, the initial pre-stresses are removed because of permanent compressive deformation in rubber. For three types of the old coupler models without the initial pre-stress, we evaluated dynamic performances of each type. As the results, the maximum and average acceleration levels of the double type and the ring type were similarly low in all conditions. But the accelerations of the single type coupler was high when compared to those of the double and ring types. In addition, Jerk value of the single type model associated with ride quality was high up to 15 times to the ring type in condition of the service braking in empty vehicle weight. Jerk value of the double type model was high up to 6 times to the ring type.

• 산업경영시스템학회지
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• 제21권45호
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• pp.165-180
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• 1998

To make a scheduling for minimizing the tardiness of delivery, we present an efficient heuristic algorithm for job-shop scheduling problems with due dates. The SDME(Slack Degree Modified Exchange) algorithm, which is the proposed heuristic algorithm, carries out the operation in two phases. In the phase 1, a dispatching rule is employed to generate an active or non-delay initial schedule. In the phase 2, tasks selected from a predetermined set of promising target operations in the initial schedule are tested to ascertain whether, by left-shifting their start times and rearranging some subset of the remaining operations, one can reduce the total tardiness. In the numerical example, the results indicate that the proposed SDME algorithm is capable of yielding notable reductions in the total tardiness for practical size problems.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 가을학술발표대회논문집
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• pp.105-106
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• 2023

In project projects where various factors arise, the construction company's initial establishment of a reasonable process plan reduces various variables and potential risks. In order to create a densely written initial process plan, it is necessary to compare the economic feasibility of time and money by reflecting Slack time. Through this, site managers can lead a successful project based on reasonable and stable construction.

• 한국경영과학회지
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• 제27권2호
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• pp.153-171
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• 2002

In this paper, we present an efficient pricing strategy, the pivot and probe Algorithm for Network Flow Problems(PAPANET), specifically for solving capacitated, linear network flow problem (NPs). The PAPANET begins with an initial relaxed network problem(RNP), consisting of all the nodes and initial candidate arcs(possibly a few least cost arcs form the original problem and a set of all the artificial and slack arcs). After an initial solution to the RNP is derived by pivoting, the PROBE procedure identifies a set of most violated arcs from the noncandidate arcs that are not considered to be in the current RNP, and adds them to the RNP. The procedure also discards a set of least favorable, zero flow, nonbasic arcs from the RNP. The new RNP is solved to optimality and the procedure continues until all of the dual constraints of the noncandidate arcs are satisfied by the dual solution to the RNP. The PAPANET effectively reduces the problem size, time per pivot, and solution CPU time by eliminating noncandidate arcs. Computational tests on randomly generated problems indicate that PAPANET achieves and average savings of 50-80% of the solution CPU time of that of a comparable standard network simplex implementation.

• 대한전기학회논문지:전력기술부문A
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• 제50권9호
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• pp.424-430
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• 2001

A multi-level optimal power flow(OPF) algorithm has been evolved from a simple two stage optimal Power flow algorithm for constrained power economic dispatch control. In the proposed algorithm, we consider various constraints such as ower balance, generation capacity, transmission line capacity, transmission losses, security equality, and security inequality constraints. The proposed algorithm consists of four stages. At the first stage, we solve the aggregated problem that is the crude classical economic dispatch problem without considering transmission losses. An initial solution is obtained by the aggregation concept in which the solution satisfies the power balance equations and generation capacity constraints. Then, after load flow analysis, the transmission losses of an initial generation setting are matched by the slack bus generator that produces power with the cheapest cost. At the second stage we consider transmission losses. Formulation of the second stage becomes classical economic dispatch problem involving the transmission losses, which are distributed to all generators. Once a feasible solution is obtained from the second stage, transmission capacity and other violations are checked and corrected locally and quickly at the third stage. The fourth stage fine tunes the solution of the third stage to reach a real minimum. The proposed approach speeds up the two stage optimization method to an average gain of 2.99 for IEEE 30, 57, and 118 bus systems and EPRI Scenario systems A through D testings.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 C
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• pp.926-928
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• 1998

A fast optimization algorithm has been evolved from a simple two stage optimal power flow(OPF) algorithm for constrained power economic dispatch. In the proposed algorithm, we consider various constraints such as power balance, generation capacity, transmission line capacity, transmission losses, security equality, and security inequality constraints. The proposed algorithm consists of four stages. At the first stage, we solve the aggregated problem that is the crude classical economic dispatch problem without considering transmission losses. An initial solution is obtained by the aggregation concept in which the solution satisfies the power balance equations and generation capacity constraints. Then, after load flow analysis, the transmission losses of an initial generation setting are matched by the slack bus generator that produces power with the cheapest cost. At the second stage we consider transmission losses. Formulation of the second stage becomes classical economic dispatch problem involving the transmission losses, which are distributed to all generators. Once a feasible solution is obtained from the second stage, transmission capacity and other violations are checked and corrected locally and quickly at the third stage. The fourth stage fine tunes the solution of the third stage to reach a real minimum. The proposed approach speeds up the coupled LP based OPF method to an average gain of 53.13 for IEEE 30, 57, and 118 bus systems and EPRI Scenario systems A through D testings.

• 대한기계학회논문집A
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• 제27권8호
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• pp.1281-1286
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• 2003

A line search algorithm to increase a convergence in Newton's method is developed and applied to nonlinear finite element analysis. The algorithm is based on the slack line search theory which is an efficient algorithm to determine initial acceleration coefficient, variable backtracking algorithm proposed by some researchers, and convergence criterion based on residual norm. Also, it is capable of avoiding exceptional diverging conditions. Developed program is tested in metal forming simulation such as forging and ring rolling. Numerical result shows the validity of the algorithm for a highly nonlinear system .