• Journal of the military operations research society of Korea
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• v.12 no.2
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• pp.68-81
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• 1986

This thesis studies the estimation from interarrival and service time data of the mean number of customers in service at time t for an $M/G/{\infty}$ queue. The assumption is that the parametric form of the service time distribution is unknown and the empirical distribution of twe service time is used in the estimate the mean number of customers in service. In the case in which the customer arrival rate is known the distribution of the estimate is derived and an approximate normal confidence interval procedure is suggested. The use of the nonparametric methods, which are the jackknife and the bootstrap, to estimate variability and construct confidence intervals for the estimate is also studied both analytically and by simulation.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.7
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• pp.510-514
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• 2009

If the existing real-time systems are integrated based on SOA, real-time SOA should be developed. Generally, in real-time SOA a service can be divided into several small services and their estimated execution time is given by provider systems. However, an estimation, which analyzes time elements related to transmit and receive messages among requesters and providers, is needed. In order to enhance QoS of Web service, this paper proposes enhanced worst-case execution time estimation by considering WS-transaction and common use of multi-processors system.

• KIEAE Journal
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• v.14 no.5
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• pp.5-12
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• 2014

Building has been deteriorated gradually owing to geographic, physical complex and other factors. School living condition has a key role to improve the learning ability, life attitude and qualifications to adopt to social life. Therefore, it is important for school environment to keep the living condition. Repair time and scope of school facilities are required to maintain the function and performance to plan the long term repair. But there are little information about the school maintenance such as repair time and function. In this paper, it aimed at providing the service life to suggest the repair time and scope in the roof-proofing and floor finishing which used the three estimation method in probabilistic approach. The service life has a key role to decide the repair time and to make the plan for the repair maintenance. Results of this study are as follows ; First, the 1st repair time were taken through three methods in probabilistic and deterministic functions to eliminate the estimation bias. Second, the service life is suggested 36 years of an elementary school, 34 years of a middle school and 41 years of a high school. Third, the service life of a floor finishing is 43 years of an elementary, 39 years of a middle school and 41 years of a high school. The above study could not include the detailed information about the materials and repair works. Therefore it needs a further study to reflect the detailed information and to make a repair strategy.

• International Journal of Automotive Technology
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• v.3 no.4
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• pp.129-135
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• 2002

Durability estimation of a prototype vehicle has traditionally relied heavily on accelerated durability tests using predefined proving grounds or rig tests using a road simulator. By use of those tests, it is very difficult to predict durability failures in actual service environments. This motivated the development of an integrated CAE (Computer Aided Engineering) methodology for the durability estimation of a prototype vehicle in actual service environments. Since expensive computational costs such as computation time and hardware resources are required for a full vehicle simulation in those environments with a very long span of event time, the conventional CAE methodologies have little feasibility. An efficient computational methodology for durability estimations is applied with theoretical developments. The effectiveness of the proposed methodology is shown by the comparison of results of the typical actual service environment such as the city mode with those of the typical accelerated durability test over the Belgian road.

• Journal of Information Technology Services
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• v.10 no.4
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• pp.243-258
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• 2011

With increasing interest in ubiquitous computing technology, an infrastructure for the short-distance wireless communication has been extended socially, bringing spotlight to the security system using the image or location. In case of existing security system, there have been issues such as the occurrences of blind spots, difficulty in recognizing multiple objects and storing of the unspecified objects. In order to solve this issue, zone-based location-estimation search system for the image have been suggested as an alternative based on the real-time location determination technology combined with image. This paper intends to suggest the search service for the image zone-based location-estimation. For this, it proposed the location determination algorism using IEEE 802.15.4/ZigBee's RSSI and for real-time image service, the RTP/RTCP protocol was applied. In order to combine the location and image, at the event of the entry of the specified target, the record of the time for image and the time of occurrence of the event on a global time standard, it has devised a time stamp, applying XML based meta data formation method based on the media's feature data based in connection with the location based data for the events of the object. Using the proposed meta data, the service mode which can search for the image from the point in time when the entry of the specified target was proposed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3B
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• pp.288-303
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• 2009

In the near future it is foreseen that a genuine multimedia service over the WiMAX system is provided in a worldwide manner by exploiting the QoS technologies introduced in the wireless and wired broadband network. In this work we propose a pricing scheme for the multimedia service over the generic WiMAX system that supports a full QoS functionality. We assume real-time services such as the voice and video as well as the nonreal-time service such as the conventional high-speed data, and we propose a pricing and charging scheme for those services by investigating the inherent characteristics of those services and the multiple-class of QoS-service provided to them. After that we propose a method to compute expected revenue that is obtained from the WiMAX system by using an analytic method to estimate the usage of the bandwidth resources for the different class of services. Via numerical experiment, we verify the implication of the work.

• The Journal of Society for e-Business Studies
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• v.17 no.2
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• pp.149-163
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• 2012

Logistics systems provide their service to customers by coordinating the resources with limited capacity throughout the underlying processes involved to each other. To maintain the high level of service under such complicated condition, it is essential to carry out the real-time monitoring and continuous management of logistics processes. In this study, we propose a method of estimating the service completion time of key processes based on process-state information collected in real time. We first identify the factors that influence the process completion time by modeling and analyzing an influence diagram, and then suggest algorithms for quantifying the factors. We suppose the container terminal logistics and the process of discharging and loading containers to a vessel. The remaining service time of a vessel is estimated using a decision tree which is the result of machine-learning using historical data. We validated the estimation model using container terminal simulation. The proposed model is expected to improve competitiveness of logistics systems by forecasting service completion in real time, as well as to prevent the waste of resources.

• Korean Management Science Review
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• v.22 no.1
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• pp.179-197
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• 2005

This study examines market acceptance for DMB service, one of the touted new business models in Korea's next-generation mobile communications service market, using adoption end diffusion of innovation as the theoretical framework. Market acceptance for DMB service was assessed by predicting the demand for the service using the Bass model, and the demand variability over time was then analyzed by integrating the innovation adoption model proposed by Rogers (2003). In our estimation of the Bass model, we derived the coefficient of innovation and coefficient of imitation, using actual diffusion data from the mobile telephone service market. The maximum number of subscribers was estimated based on the result of a survey on satellite DMB service. Furthermore, to test the difference in diffusion pattern between mobile phone service and satellite DMB service, we reorganized the demand data along the diffusion timeline according to Rogers' innovation adoption model, using the responses by survey subjects concerning their respective projected time of adoption. The comparison of the two demand prediction models revealed that diffusion for both took place forming a classical S-curve. Concerning variability in demand for DMB service, our findings, much in agreement with Rogers' view, indicated that demand was highly variable over time and depending on the adopter group. In distinguishing adopters into different groups by time of adoption of innovation, we found that income and lifestyle (opinion leadership, novelty seeking tendency and independent decision-making) were variables with measurable impact. Among the managerial variables, price of reception device, contents type, subscription fees were the variables resulting in statistically significant differences. This study, as an attempt to measure the market acceptance for satellite DMB service, a leading next-generation mobile communications service product, stands out from related studies in that it estimates the nature and level of acceptance for specific customer categories, using theories of innovation adoption and diffusion and based on the result of a survey conducted through one-to-one interviews. The authors of this paper believe that the theoretical framework elaborated in this study and its findings can be fruitfully reused in future attempts to predict demand for new mobile communications service products.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.238-239
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• 2013

A system to efficiently utilize construction information has been in demand as a result of the changing society where information and knowledge leads to added value. Consequently, the government established a comprehensive information network system for construction industries to manage and utilize construction information which is the currently in use. However, this system is oriented toward management and business performance estimation for engineering and does not integrate a management system for design, construction technology, and construction engineering services. Therefore, this study proposes to develop object technology and management system of construction services and its evaluation to provide such information in real time.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.168-169
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• 2014

Construction Technology Service is currently hardly managed due to failure to offer standard management system of service performance, company performance, and business evaluation in every Ordering Agencies. After Construction Technology Promotion Act is enforced in May 2014, Ordering Agency obligates them to report to Minister of Land and Transportation within 10 days upon contract/ amendment/ completion. In 2013, in advance to enforcement of this law, performance management system for construction technology service was developed for a test run. However this system only applies to main contractors while management and operation of subcontractors are unavailable that causes problems on connection and integration with Experience Management Trustee. Therefore, this research will establish systematic foundation that enables real-time information of service performance and evaluation of subcontractors to result standardization of performance and evaluation for public ordered services.