• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.13 no.3
• /
• pp.1345-1362
• /
• 2019

Most active queue management algorithms manage network congestion based on the size of the queue but ignore the network environment which makes queue size change. It seriously affects the response speed of the algorithm. In this paper, a new AQM algorithm named CT-AQM (Change Trend-Adaptive Queue Management) is proposed. CT-AQM predicts the change trend of queue size in the soon future based on the change rate of queue size and the network environment, and optimizes its dropping function. Simulation results indicate that CT-AQM scheme has a significant improvement in loss-rate and throughput.

• The KIPS Transactions:PartD
• /
• v.17D no.4
• /
• pp.271-282
• /
• 2010

Insufficient requirement management accounts for 54% ofunsuccessful software development projects and 22% of insufficient requirement management comes from requirement change management. Hence, requirement management activities are important to reduce failure rates and a tracing method is suggested as the major factor in requirements change management. A traceability table is easy to use because of its legibility accurate tracing. However, traceability tables of existing studies have failed to concretely suggest method of change management and effect of traceability. Also, studies of methods to estimate change impact is complex. Hence, this study suggests how to use a traceability table to manage changes in requirements. Together, in comparison to existing studies, this study suggests easier methods to estimate change rate and change impact. Also Fifteen projects were sampled to test the hypothesis that traceability table influences the success of projects and that it decreases the failure rate that comes from the insufficient requirements management.

• Journal of Information Technology Applications and Management
• /
• v.14 no.3
• /
• pp.1-14
• /
• 2007

Recently. interests in IT Service Management (ITSM) are increasing internationally as well as domestically. In order to realize the benefits from ITSM, it is necessary to institutionalize it as a culture of the organization through effective change management. One of the most promising approach of effective change management is a Six Sigma technique. In this study, we analyze a success case in which 6 Sigma was applied to Service Desk function which is one of the most important functions of ITSM. Through the analyses, this study aims to propose a feasible and specific approach to institutionalize ITSM. To accomplish the objective. the study analyzed specific methods of application of 6 Sigma to ITSM. performance of the project and future directions based on interview and project document/deliverable review. This study could not provide detailed performance measures due to lack of previous research on this topic and difficulty of obtaining quantitative data. However. this study has contributed to proposing a direction to institutionalize ITSM in organizations by analyzing a feasibility of 6 Sigma in implementing ITSM.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2000.04a
• /
• pp.397-400
• /
• 2000

This paper provides a product data representation, a data schema and related operations, for the management of engineering changes. The computer Interpretable format of the representation enables itself to be realized through databases and their applications to a component of a product data management system. Supporting general operations for the engineering changes, it resolves problems of the existing information systems in the nested engineering changes and the simultaneous change application to multiple products. To show the feasibility, a prototype system is implemented based on the representation.

• Asia pacific journal of information systems
• /
• v.23 no.2
• /
• pp.87-109
• /
• 2013

While many surveys show very positive attitudes on the part of consumers towards eco-friendly products, the market share actually reflecting green IT purchases remains low in most countries. The motivations behind green IT purchase behavior are still obscure. Several studies have addressed the question of green IT diffusion from economic and normative viewpoints in an attempt to interpret IT adoption behavior. This study comes at the question from a different angle, namely negative frame, examining threat and coping behaviors using the Ordered Protection Motivation (OPM) model and threat appraisal theory. The results show that attitudes toward fairness and positive change, which are precedents of threat appraisal, play an important role in determining threat appraisal. Perceived threats in the green IT arena include habit change and ecological change. Appraisal for coping with these threats directly affects initial adoption behaviors regarding available green IT, and then indirectly encourages the purchase of new green IT products.

• Journal of Korean Society for Quality Management
• /
• v.30 no.3
• /
• pp.195-202
• /
• 2002

The problem of trend change in the mean residual life is great Interest in the reliability and survival analysis. In this paper, a new test statistic for testing whether or not the mean residual life changes its trend Is developed. It is assumed that neither the change point nor the proportion at which the trend change occurs is known. The asymptotic null distribution of test statistic is established and asymptotic critical values of the asymptotic null distribution is obtained. Monte Carlo simulation is used to compare the proposed test with previously known tests.

• Journal of Korean Society for Quality Management
• /
• v.30 no.4
• /
• pp.78-85
• /
• 2002

The problem of trend change in the mean residual life is great interest in the reliability and survival analysis. In this paper, a new test statistic for testing whether or not the mean residual life changes its trend is developed. It is assumed that neither the change point nor the proportion at which the trend change occurs is known. The asymptotic null distribution of test statistic is established and asymptotic critical values of the asymptotic null distribution is obtained. Monte Carlo simulation is used to compare the proposed test with previously known tests.

• Korean Management Science Review
• /
• v.18 no.1
• /
• pp.119-133
• /
• 2001

It is important to find the equilibrium level of real interest rate for it affects real and financial sector of economy. However, it is difficult to find the equilibrium level because like the most macroeconomic model the real interest model has parameter instability problem caused by structural change and it is supported by various theories and definitions. Hence, in order to cover these problems structural change detection model of real interest rate is developed to combine the real interest rate equilibrium model and the procedure to detect structural change points. 3 equations are established to find various effects of other interest-related macroeconomic variables and from each equation, structural changes are found. Those structural change points are consistent with common expectation. Oil Crisis (December, 1987), the starting point of Economic Stabilization Policy (January, 1982), the starting point of capital liberalization (January, 1988), the starting and finishing points of Interest deregulation (January, 1992 and December, 1994), Foreign Exchange Crisis (December, 1977) are detected as important points. From the equation of fisher and real effects, real interest rate level is estimated as 4.09% (October, 1988) and dependent on the underlying model, it is estimated as 0%∼13.56% (October, 1988), so it varies so much. It is expected that this result is connected to the large scale simultaneous equations to detect the parameter instability in real time, so induces the flexible economic policies.

• International conference on construction engineering and project management
• /
• 2009.05a
• /
• pp.1283-1287
• /
• 2009

The Korean government implemented 259 road projects from 2004 to 2007, valued at $18.4 billion. Change orders of these road projects occurred 8,973 times and, subsequently, caused significant increases in the cost of the projects, approximately up to $4.2 billion (22.8% of the initial budget). These significant problems of huge change orders require a more workable control system for budget management whereas the effectiveness of the government's control is still not satisfied. However, previous approaches and studies mostly limited their analyses to simply classifying the causes of the change orders. This paper investigates the real frequency and cost impacts incurred by each cause of a change order, primarily based on 218 road projects in Korea. The paper then identifies the attributes of change orders through a survey of 204 project participants in that those sources were inevitable or avoided if properly managed. The causes of the change orders are further analyzed with analysis of variance (ANOVA) in connection with contract volume, bid award rate, the contractor's capacity to perform, and the design company's capacity. This study found that if the contract volume is smaller, then the possibility of change orders is higher. Interestingly, if the bid award rate is less than 67.5%, it signifies the highest rate of change orders. In addition, the contractors whose construction ability is assessed as the top-ranked group showed the lowest change order rates. With these results, this paper provides the preventive guidelines for reducing the likelihood of change orders.

• Knowledge Management Research
• /
• v.6 no.2
• /
• pp.91-108
• /
• 2005

In recent years, organizations have chosen a team-organization as a standard activity level and it leads a significant change in process of knowledge producing. Nevertheless team-organization for building up effective performance and a good communication in organization has influenced knowledge management performance, the empirical analysis and survey have not proved yet. This study, therefore, makes an analysis that the change of organization base on team activity influences knowledge management performance. This study, based on 312 data by using LISREL as a model for studying, provides a result that a team-based activity positively influences knowledge management efficiency.