• Journal of the Korean Operations Research and Management Science Society
• /
• v.14 no.2
• /
• pp.97-104
• /
• 1989

This paper extends the existence proofs of a Nash equilibrium to a more general class of differentila game models with constraints on the control spaces. With the assumptions of continuity, convexity, and compactness, the existence is proved using Kakutani Theorem and via a path-following approach. Furthermore, the proof for a period-by-period optimization of multi-period problems provides an insight to a numerical solution algorithm to differential game models with constraints.

• Management & Information Systems Review
• /
• v.28 no.3
• /
• pp.25-44
• /
• 2009

The purpose of this paper is to examine the determinants which cause a price differential between common and preferred stock. Prior studies have shown that variables like liquidity, size, the number of outstanding shares issued can explain the price differential between common and preferred stock price. Based on year 2006 through year 2008 data, we analyzed the determinants using regression model. Dummy variables representing large/small company and KSE/KOSDAQ respectively are added and analyzed as independent variables. The firm size, trade volume turnover, and the number of preferred shares to total outstanding shares were proved to make influence on the price differential under the 5% significance level. Especially, we have found the number of preferred shares to total outstanding shares provide the most strong relationship with the price differential. This means that a high ratio of preferred stock to total outstanding shares leads to relatively high value of common stock and causes a big price differential.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2008.11a
• /
• pp.1332-1335
• /
• 2008

In order to various service types of real time and non-real time traffic with varying requirements are transmitted over the IEEE 802.16 standard is expected to provide quality of service(QoS) researchers have explored to provide a queue management scheme with differentiated loss guarantees for the future Internet. The sides of a packet drop rate, an each class to differential drop probability on achieving a low delay and high traffic intensity. Improved a queue management scheme to be enhanced to offer a drop probability is desired necessarily. This paper considers multiple random early detection with differential drop probability which is a slightly modified version of the Multiple-RED(Random Early Detection) model, to get the performance of the best suited, we analyzes its main control parameters (max_th, min_th, max_p) for achieving the proportional loss differentiation (PLD) model, and gives their setting guidance from the analytic approach. we propose Dynamic-multiple queue management scheme based on differential drop probability, called Dynamic-VQSDDP(Variable Queue State Differential Drop Probability)T, is proposed to overcome M-RED's shortcoming as well as supports static max_p parameter setting values for relative and each class proportional loss differentiation. M-RED is static according to the situation of the network traffic, Network environment is very dynamic situation. Therefore max_p parameter values needs to modify too to the constantly and dynamic. The verification of the guidance is shown with figuring out loss probability using a proposed algorithm under dynamic offered load and is also selection problem of optimal values of parameters for high traffic intensity and show that Dynamic-VQSDDP has the better performance in terms of packet drop rate. We also demonstrated using an ns-2 network simulation.

• Journal of Korean Society for Quality Management
• /
• v.32 no.3
• /
• pp.182-197
• /
• 2004

In this paper we propose a new method of evaluating customers' service quality using triangle fuzzy numbers and semantic differential scale. These two parameters are useful for quantifying the customers' linguistic variables and subjective judgements. We define the Service Quality(SQ) as the ratio of the expected and perceived service and address the Agreement Rate(AR) calculated from the hamming distance in order to define the Service Rate(SR) as the geometric mean of the SQ and AR. Using the SR in the analysis of service attributes provides more appropriate to measure the customers' service quality and to establish a creative service policy for competitive service quality improvement.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.4 no.4
• /
• pp.21-29
• /
• 2008

The DC characteristics of GaAS Gunn diode are investigated as a preliminary study on the planar grade gap injector GaAs Gunn diode which is the transferred electron device with high output power and dc-rf conversion efficiency. The Gunn devices we fabricated were confirmed to have the DC characteristics of negative differential resistance(NDR). We discussed the nature of the NDR effect, including the electron intervalley transfer; the NDR effect was examined for six different cathode radii.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.21 no.1
• /
• pp.31-50
• /
• 1996

In this paper we prescribe a replication server scheme with an algorithm DRF (Differential Refresh File) to refresh multiple materialized views and replicas in distributed environments. Before sending relevant tuples in server sites to client sites, an effective tuple reduction scheme is developed as a preprocessor to reduce the transmission cost. Because it utilizes differential files with out touching base relations, the DRF scheme can help to minimize the number of locks, which enhances the system's performance.

• Proceedings of the SAREK Conference
• /
• 2008.06a
• /
• pp.463-467
• /
• 2008

The fact that the major cases of life casualties are from smoke in the fire accidents and the expected steep increase of skyscrapers, huge spaces, multiplexes and huge scaled underground spaces demand establishment of efficient smoke countermeasure. The field experiments on pressure differential systems for smoke management in two high buildings of 20 stories and 21 stories are carried out to evaluate the features of airflow through open door between accommodation and lobby. The procedures and results of experiments are presented.

• Proceedings of the SAREK Conference
• /
• 2008.11a
• /
• pp.463-468
• /
• 2008

The fact that the major cases of life casualties are from smoke in the fire accidents and the expected steep increase of skyscrapers, huge spaces, multiplexes and huge scaled underground spaces demand establishment of efficient smoke countermeasure. In pressure differential systems for smoke management, the speed of airflow through open door between accommodation and lobby should be maintained over 0.5m/s on the whole area of door to prevent smoke from infiltrate into evacuation root when the door is open for refuge. The numerical analysis on features of airflow through open door are carried out and the results are presented.

• Journal of applied mathematics & informatics
• /
• v.42 no.4
• /
• pp.899-913
• /
• 2024

In this article, the Series Solution Method (SSM) is employed to solve the linear or non-linear Volterra integro-differential equations. Numerous examples have been presented to explain the numerical results, which is the comparison between the exact solution and the numerical solution, and it is found through the tables. The amount of error between the exact solution and the numerical solution is very small and almost nonexistent, and it is also illustrated through the graph how the exact solution completely applies to the numerical solution. This proves the accuracy of the method, which is the Series Solution Method (SSM) for solving the linear or non-linear Volterra integro-differential equations using Mathematica. Furthermore, this approach yields numerical results with remarkable accuracy, speed, and ease of use.

• KIEAE Journal
• /
• v.15 no.6
• /
• pp.87-92
• /
• 2015

Purpose: The green building certification system in Korea was introduced in 2002 and developed as an improvement version of the G-SEED(Green Standard for Energy and Environmental Design) system in 2013. This study conducts surveys targeting architectural designers and users on significance of certification assessment criteria for apartment buildings on the G-SEED system and examines the differential views between the two groups on assessment criteria. Method: First, The AHP(Analytic Hierarchy Process) method was used to find importance of assessment criteria and then the importances were compared with weighted points on the certification standard. Second, the t-test was used to investigate differential views between designer and user groups on certification assessment criteria based on drawn importances. Result: (1) While designer group considered land use and transportation, energy and environmental pollution, and water circulation management as more important, user group did material and resource, maintenance management, ecological environment, and indoor environment as more important. (2) Based on t-test results, sustainable energy, water circulation system, site management, habitat, acoustical environment, and light environment were found to be different on importance between the two groups.