• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.14 no.24
• /
• pp.149-154
• /
• 1991

The one of the important problems in the design of queueing systems is the decision of the order of service stations. The object of this problem is the decision of the order that minimizes the expected sojourn time per customer in the given arrival process and service time distributions. In this paper, the tandem queueing system in series is studied with the emphasis on the optimal order of the tandem queueing system which has three stations with single servers. In one system, customers arrive at the first station with Poisson process. This system is composed of service stations with a constant, a general distribution and a Exponential distribution is studied. To select the optimal order after the orders of each pair of two stations is decided, it is compared the two orders of system. With this results, total expected delay of the systems which has three stations is compared. The result is the best that service station with constant time is on the first place, then the service station with general distribution and the service station with Exponential distribution is followed. And the other system is consist of service stations with a constant and two probabilistic distributions. In this case, two probabilistic distributions has a non-overlapping feature. It is the optimal order that the service station with constant time is on the first place then the service station with longer service time and the service station with shorter service time is followed.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.22 no.49
• /
• pp.43-57
• /
• 1999

The recent trend is that risk management has more and more its importance. Neverthless, Korea's risk management is not developed. Even most banks does gap, duration in ALM for risk management, development and operation of VaR stressed at BIS have elementary level. In the case of Fallon and Pritsker, Marshall, gamma model is superior to delta model and Monte Carlo Simulation is improved at its result, as sample number is increased. And, nonparametric model is superior to parametric model. In the case of Korea's stock portfolio, VaR of Monte Carlo Simulation and Full Variance Covariance Model is less than that of Diagonal Model. The reason is that VaR of Full Variance Covariance Model is more precise than that of Diagonal Model. By the way, in the case of interest rate, result of monte carlo simulation is less than that of delta-gamma analysis on 95% confidence level. But, result of 99% is reversed. Therefore, result of which method is not dominated. It means two fact at forecast on volatility of stock and interest rate portfolio. First, in Delta-gamma method and Monte Carlo Simulation, assumption of distribution affects Value at Risk. Second, Value at Risk depends on test method. And, if option price is included, test results will have difference between the two. Therefore, If interest rate futures and option market is open, Korea's findings is supposed to like results of other advanced countries. And, every banks try to develop its internal model.

• Land and Housing Review
• /
• v.11 no.4
• /
• pp.15-26
• /
• 2020

This study analyzes the Domestic Economic Ripple Effect (DERE) of the Donghae-Bukpuseon Railway (DBR). Input-Output Analysis and Scenario Analysis are employed. First, the future demand is approximately 6.86 billion people, 1.4 billion tons of logistics, and future forecast production is 1.2 trillion won for passengers, and 0.15 trillion won for logistics. Second, the production inducement (PI) coefficient of the railway industry is 2.080, the value-added inducement (VAI) coefficient is 0.680, the import inducement (II) coefficient is 0.32 and the employment inducement (EI) coefficient is 6.45. Third, for the DERE, PI is 2.846 trillion won, VAI is 0.939 trillion won, II is 0.446 trillion won, and EI is 8,737 people/1 billion won. Fourth, PI is approximately 2.8 trillion won, and the payback period is 35 years. Scenario 1 (a 50% increase in the demand for tourism) takes approximately 27 years, Scenario 2 (an 100% increase), 20 years, and Scenario3 (an 150% increase), 16 years. The successful way of the DBR is to enlarge the linkage effect of trans-railways for which international cooperation and agreements are needed. Also, even if the DBR is isolated due to worsening inter-Korea relations, the development of tourism resources is important for public investment feasibility.

• Journal of the Korean Society of Visualization
• /
• v.18 no.3
• /
• pp.77-83
• /
• 2020

A uniflow cyclone has simple structure with a single channel in one direction. The one directional particle removal enables the uniflow cyclone to have compact size and low pressure drop. However, it has low collection efficiency compared to conventional cyclones. In this study, the effect of primary geometry on the performance of a uniflow cyclone with swirl vane is numerically investigated for the design of high performance uniflow cyclone. It is found that as the vortex finder diameter is increased, the pressure drop and the collection efficiency are decreased. Also, the same trend is predicted when the vortex finder height is increased. The best collection efficiency is predicted to be obtained when the vortex finder height is equal to the diameter of a cyclone. Reducing the body height by half will increase the pressure drop by 41%. When the body height is decreased, the collection efficiency is first increased and then decreased. The best collection efficiency is obtained when the body height is 4~5 times the cyclone diameter. Overall, the particle collection efficiency is highest when the Dν/D is equal to 0.3. But, the pressure drop is as high as 1592 Pa. Considering both collection efficiency and pressure drop, the best design is when Dν/D, Hν/D, and Hb/D are equal to 0.5, 1, and 5, respectively.

• (The)Study of the Eastern Classic
• /
• no.67
• /
• pp.327-344
• /
• 2017

Zhou Dunyi is regarded as a precursor of Li-Xue, which is called Neo-Confucianism. So, it could be say that Zhou Dunyi is a precursor of Song-Ming-Li-Xue. As is well known, Zhu xi is a synthesizer of Li-Xue in Song Dynasty, which is called Dao-Xue; Wang Yangming is a synthesizer of Li-Xue in Ming Dynasty, which is called Xin-Xue. Dao-Xue and Xin-Xue were engaged in an unyielding confrontation for many centuries in Asian areas. It is certain that Dao-Xue and Xin-Xue both succeed to the resources of Zhou Dunyi together, but it is not easy to confirm that the resources of Zhou Dunyi are common to both sides taking an unyielding confrontation into consideration. Usually, Zhou Dunyi is recognized as a Master of Dao-Xue rather than Xin-Xue. But in this paper, I try to give a question to this prevalent view, like this: Yang-Ming-Xin-Xue much absorbed and developed the Thought of Zhou Dunyi than Zhu-Xi-Dao-Xue did. In order to prove this assertion, I take two steps. The first is about Daotong, the second is about sincerity. In conclusion, while Wang Yangming build his own thought of moral philosophy, he fully absorbed Zhou Dunyi's thought of sincerity, and concreted his typical moral philosophy, which is Liangzhi-Xue. I could say that besides the viewpoint of Zhu xi, there is another viewpoint of Wang Yangming to understand the thought of Zhou Dunyi properly.

• Asia pacific journal of information systems
• /
• v.34 no.1
• /
• pp.49-90
• /
• 2024

Intradisciplinary research refers to research that integrates ideas often associated with different research domains in a discipline. Such cross-fertilization leverages abundant diversity present in the IS discipline to tackle increasingly complex IS problems and grand challenges. Despite its importance and recent attention, a concerted, sustained effort toward intradisciplinary research is lagging. A fundamental issue we see is a lack of an elaborate IS research map that effectively shows similarities and differences among research domains and demonstrates types of ideas that may travel and integrate into different domains. We thus aim to propose an elaborate IS research map and compile research elements that can be tried and combined across research domains. To do so, we utilize two IS classics (i.e., IT views and IS phenomena), identify their complementarity, and interweave the two disparate ways of portraying the IS research field. The resultant view-phenomenon (VP) matrix specifies research domains based on two consistent, comprehensive criteria and helps researchers discern similarities and differences among research domains more effectively. The VP matrix also sheds light on a variety of research elements that can flow across research domains. The VP matrix along with the research elements together facilitate intradisciplinary efforts and, more broadly, help the IS discipline to prosper. The VP matrix is particularly helpful for doctoral students and young scholars.

• Journal of Korean Society for Quality Management
• /
• v.16 no.2
• /
• pp.92-98
• /
• 1988

In this paper a model is developed for an inventory system in which the number of units of acceptable quality in a replenishment lot is uncertain and the demand. during the stockout period is back ordered and. also under the same condition an inventory model with experdited stockout is developed. It is assumed that the fraction of the acceptable quality in a replenishment lot is a random variable whose probability distribution is known. The optimal replenishment policy is synthesized for such a system. A numerical example is used to illustrate the theory.

• Bulletin of the Korean Mathematical Society
• /
• v.37 no.3
• /
• pp.587-599
• /
• 2000

In this paper we study some nonpositively curved Riemannian manifolds acted on by a Lie group of isometries with principal orbits of codimension one. Among other results it is proved that if the universal covering manifold satisfies some conditions then every nonexceptional singular orbit is a totally geodesic submanifold. When M is flat and is not toruslike, it is proved that either each orbit is isometric to $R^k\timesT^m$or there is a singular orbit. If the singular orbit is unique and nonexceptional, then it is isometric to $R^k\timesT^m$.

• 제어로봇시스템학회:학술대회논문집
• /
• 1998.10a
• /
• pp.373-378
• /
• 1998

A method to construct a memoryless feedback law for systems with multiple time-delays in the states is proposed. As a plant model, a differential-difference equation with multiple delayed terms is introduced, A stabilizability condition by memoryless feedback is presented. A feedback gain is calculated with a solution of a finite dimensional Riccati equation. It is shown that the resulting closed loop system is asymptotically stable, and moreover, it is a linear quadratic regulator for some cost functional. An alternative stabilizability condition which is easier to check is given.

• Journal of the Korean Society of Industry Convergence
• /
• v.5 no.1
• /
• pp.75-80
• /
• 2002

In this study, the initial number of bacteria before ozone sterilizing shows 290 per $1m{\ell}$ in RUN 1 and RUN 2 equally, but the removal rate shows more than 50% in RUN 1, and 100% in RUN 2 respectively when ozone injection amount is $0.28mg/{\ell}$. It is regarded as a satisfactory result that E-coli concentration without ozone contact is 890, rapid removal effect of E-coli is observed in $0.28mg/{\ell}$ of ozone, and E-coli is removed perfectly in $0.84mg/{\ell}$ of ozone. It is thought that an excellent efficiency is obtained for vibrio alginolyticus because the initial number of bacteria before ozone contact is positive, but it is altered to negative after ozone contact. CODcr shows the tendency which is somewhat reduced as the ozone injection is increased, but the general effect is appeared not so much, and it is thought that the tendency is caused by the reason that sea water contains much salt which is estimated as a component of CODcr, therefore it is regarded that ozone contact has not an important effect on salinity. It is thought that the frequency of changing salt water in the fish preserve of a sliced raw fish restaurant can be reduced to under the standard because NTU of 7 days after sea water injection is 0.70 in the experiment of turbidity, hut more than 50% of turbidity removal efficiency is appeared at $0.28mg/{\ell}$ of ozone injection, and it shows 70% at $0.84mg/{\ell}$ of ozone injection in RUN 1 and RUN 2 commonly.