• Journal of Broadcast Engineering
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• v.7 no.4
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• pp.327-334
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• 2002

This paper addresses an efficient loop filter algorithm to improve visual quality by simultaneously reducing blocking and ringing artifacts in H.26L video coder. H.26L video coding standard using the different coding mechanism to existing video coding standards has different distribution of blocking and ringing artifacts that is dependent on coding type, quantization step size, and motion vector. Therefore, the information is used to define the filter type and the filter coefficients. and a projection operator is defined to avoid the over-smoothness. In addition, in order to avoid over-smoothing coming from filtering processing, a constraint projection operator is defined. Since the above information is available both in encoder and in the decoder, a loop filter is used, and the algorithm is simplified to reduce the computational cost. Experimental results show the capability of the proposed algorithm.

• Journal of KIISE:Information Networking
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• v.29 no.3
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• pp.277-285
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• 2002

This paper proposes and analyzes an error control scheme for the transmission control based real-time communication, such as FDDI, TDMA, and wireless LAN, which delivers the message according to the round robin fashion after the off-line bandwidth allocation. Taking into account the time constraint of each message, the proposed error control scheme makes the receiver transmit the error report via asynchronous traffic while the sender resend the requested message via overallocated access time which is inevitably introduced by the bandwidth allocation procedure for hard real -time guarantee. The error control procedure does not interfere other real -time message transmissions. In addition, as each frame contains the size of the message it belongs, the receiver can recognize the end of completion of message transmission. This enables earlier error report to the receiver so that the sender can cope with more network errors. The analysis results along with simulation performed via SMPL show that the proposed scheme is able to enhance the deadline meet ratio of messages by overcoming the network errors. Using the proposed error control scheme, the hard real -time network can be built at cost lower than, but performance comparable to the expensive dual link network.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.11
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• pp.1067-1074
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• 2010

In this study, RBDO(Reliability Based Design Optimization) was performed for a supersonic double-wedge inlet. By considering uncertainty of design with given design space, the pressure recovery was transformed into the probabilistic constraint while the inlet drag was considered as a deterministic objective function. To save computational analysis cost and to search good design space, Latin-Hypercube design of experiment and the Kriging model were incorporated and then RBDO was performed. Monte-Carlo simulation was performed to verify the accuracy of AFORM(Advanced First Order Reliability Method). It was found that AFORM result agreed very well with the Monte-Carlo simulation result. The system reliability was guaranteed by considering uncertainty of the design variables. In case of considering diverse uncertainty of system design, RBDO was found to be useful.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11B
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• pp.1596-1606
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• 2010

In this paper, we present a new analytical model that can precisely estimate the blocking performance of wavelength-routed WDM networks with sparse-partial-limited wavelength conversion (SPLWC). The proposed model accounts for the two sources of call blocking in a wavelength converter: range blocking originated from the limited conversion range of a wavelength converter; and capacity blocking induced from the limited number of wavelength converters. Based on the proposed model, we also present a new converter placement algorithm that minimizes the amount of wavelength conversion capability, while satisfying the given constraint on the network-wide blocking probability. From the numerical results obtained from the EON, we demonstrate that the blocking probability of the analytical model closely matches with that of the simulation. We also show that, by efficiently combining the existing sparse, partial, and limited wavelength conversion, the SPL WC can achieve the required blocking performance with the least amount of wavelength conversion cost.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.252-255
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• 2008

The purpose of construction project management is to achieve planned quality by adequate cost and schedule of the project, thus the effective time management is a critical factor to actualize the object. But the traditional time management by using milestone has several limitations which are not sufficiently considered mutual relation and variated from the task. On this wise, applying the concept and principles of lean construction to the project will be the best way not only reduce waste and variation, but also improve the productivity and ability to overcome limitation as mentioned above. Thus the study, Last Planner System, specially focuses on constraint analysis which is used in lookahead planning system. The results of this research will provide the constraints classification that is able to improve work reliable and percent plan complete when time planning by controlling constraints of project.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.11
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• pp.1049-1057
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• 2020

The shift from elite education to mass education in Vietnam has met the demand for education for everybody as well as for quality human resource talent for an emerging nation. Under the resource constraint, understanding the quality dimensions of education and its priority level is important for effective and efficient policies. This study was carried out using both qualitative and quantitative methodologies to develop quality criteria and a ranking model. Two rounds of in-depth interviews were conducted with fifteen experts in the field, who were rectors, employers, and recruitment specialists to develop the quality framework applied in Vietnamese universities under total quality management (TQM), starting from the input of the senior secondary school leavers, through a teaching process to the output. The first round of interviews were unstructured questionnaires designed to explore the main factors in quality assessment model. The second round affirmed the experts' agreement on the assessment model. Then, fuzzy logic was applied to rank eight criteria in the quality assessment model into priority order: cost, teaching and administrative staff, leadership, curriculum, student-related factors, internationalization, admissions, and campus. The results are critical for identifying the necessary actions to enhance the education quality and to further research on the optimal quality model.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.450-453
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• 2001

It is requested interoperability and inter-connection among technologies due to inertia and network externalities in the telecommunications industry. for that reason, firms in the telecommunications industry compete intensively against preempting their markets. Consumers' utilties can be increased, but searching or transaction cost of consumers may be decreased by standardization which is the core issue in the telecommunications. Also, standardization may prevent firms in that industry from overplus investment. However standardization may decrease the diversity of goods and technologies, so it can be the constraint factor in the consumption. In this paper, we'll examin the economic effects of standardization in the telecommunication industry and the effects to the industrial structure of standardization. After that, we'll suggest national policies in relation to standardization.

• Journal of the Korea Society of Computer and Information
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• v.15 no.5
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• pp.125-132
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• 2010

Decision problem called an optimal release policies, after testing a software system in development phase and transfer it to the user, is studied. The applied model of release time exploited infinite non-homogeneous Poisson process. This infinite non-homogeneous Poisson process is a model which reflects the possibility of introducing new faults when correcting or modifying the software. The failure life-cycle distribution used exponential and non-exponential family which has various intensity. Thus, software release policies which minimize a total average software cost of development and maintenance under the constraint of satisfying a software reliability requirement becomes an optimal release policies. In a numerical example, after trend test applied and estimated the parameters using maximum likelihood estimation of inter-failure time data, estimated software optimal release time.

• Journal of Digital Convergence
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• v.11 no.9
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• pp.159-166
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• 2013

In this paper, make a study decision problem called an optimal release policies after testing a software system in development phase and transfer it to the user. When correcting or modifying the software, finite failure non-homogeneous Poisson process model, presented and propose release policies of the life distribution, half-logistic property model which used to an area of reliability because of various shape and scale parameter. In this paper, discuss optimal software release policies which minimize a total average software cost of development and maintenance under the constraint of satisfying a software reliability requirement. In a numerical example, the parameters estimation using maximum likelihood estimation of failure time data, make out estimating software optimal release time. Software release time is used as prior information, potential security damages should be reduced.

• Journal of Radiation Protection and Research
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• v.28 no.2
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• pp.145-154
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• 2003

By optimizing the radiation protection the collective dose and individual dose could be reduced during YGN #4 $5^{th}$ outage in 2001. The collective doses for the two high radiation jobs decreased to 85% and 65% of expected doses. The proportion of workers with low dose (below 1mSv) exposure increased 4% while the proportion of workers with over 3mSv and 5mSv exposure are decreased to 2%, 1% respectively. But none is exposed over 8mSv for the annual dose. To aid decision of utilizing the robot, cost- benefit analysis was performed and reasonable point was proposed to use the robot. For the first time job, repeated ALARA meeting and mock up training were implemented to set up working procedure by identifying the trouble. To easily set up standard procedure, mockup process was videotaped and reviewed during ALARA meeting. Monitoring is a good approach to chase radiological working condition such as working time, dose rate. behavior of workers, especially for high radiation work. Those data were estimated and adjusted from the stage of work planning to mock up. At the stage of actual work the monitoring data were compared to the estimation and recorded to database. This database will not only be used as a powerful tool for dose optimization at the following outage but also as a guideline to dose constraint set up for optimization for each specific situation.