• Journal of Korean Institute of Industrial Engineers
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• v.40 no.1
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• pp.135-139
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• 2014

In a connection-oriented packet switching network, the data communication starts after a virtual circuit is established between source and destination. The virtual circuit establishment time includes the queue waiting times in the direction from source to destination and the other way around. We use this two-way queueing delay to evaluate scheduling policies of a packet switching processor through simulation studies. In this letter, we also suggest user testing functions for the packet switching processor to manage virtual circuits. By detecting error causes, the user testing helps the packet switching processor provide reliable connection-oriented services.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.4
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• pp.166-171
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• 2001

Object-oriented programming is a solution for problems in the development, maintenance, and update of large software such as power system analysis software. However, many applications in the electrical industry critically depend on the computational efficiency of the implementation. In order to be flexible and reduce the computation time, this paper represents an efficient method for constructing a Jacobian matrix and for factorizing it, and designs the class hierarchy for power system. This method is applied to four different power systems for load flow calculation. The performance of the object-oriented program developed in C++ is assessed in computer simulation.

• Journal of the Korean Society for Library and Information Science
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• v.16
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• pp.177-205
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• 1989

Retrieval effectiveness is the principal criteria for measuring the performance of an information retrieval system. This paper deals with the characteristics of 'relevance' of information and various measuring techniques of retrieval effectivess. The outlines of this study are as follows: 1) Relevance decision for evaluation should be devided into the user-oriented and the system-oriented decisions. 2) The recall-precision measure seems to be user-oriented, and the recall-fallout measure to be system-oriented. 3) Many of composite measures can not be justified III any rational manner unfortunately. 4) The Swets model has demonstrated that it yields, in general, a straight line instead of a curve of varying curvature and emphasized the fundamentally probabilistic nature of information retrieval. 5) The Cooper model seems to be a good substitute for precision and a useful measure for systems which ranked documents. 6) The Rocchio model were proposed for the evaluation of retreval systems which ranked documents, and were designed to be independent of cut-off. 7) The Cawkell model suggested that the Shannon's equation for entropy can be applied to measuring of retrieval effectiveness.

• Journal of Internet Computing and Services
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• v.15 no.4
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• pp.125-133
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• 2014

The column-oriented database storage is a very advanced model for large-volume data analysis systems because of its superior I/O performance. Traditional data storages exploit row-oriented storage where the attributes of a record are placed contiguously in hard disk for fast write operations. However, for search-mostly datawarehouse systems, column-oriented storage has become a more proper model because of its superior read performance. Recently, solid state drive using MLC flash memory is largely recognized as the preferred storage media for high-speed data analysis systems. The features of non-volatility, low power consumption, and fast access time for read operations are sufficient grounds to support flash memory as major storage components of modern database servers. However, we need to improve traditional transaction management scheme due to the relatively slow characteristics of column compression and flash operation as compared to RAM memory. In this research, we propose a new scheme called Column-aware Multi-Version Locking (CaMVL) scheme for efficient transaction processing. CaMVL improves transaction performance by using compression lock and multi version reads for efficiently handling slow flash write/erase operation in lock management process. We also propose a simulation model to show the performance of CaMVL. Based on the results of the performance evaluation, we conclude that CaMVL scheme outperforms the traditional scheme.

• The Transactions of the Korea Information Processing Society
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• v.4 no.8
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• pp.2038-2059
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• 1997

The physical attributes of a computer, such as processor speed, size and access time of memory, and I/O bandwidth, are fixed when the computer is delivered to the user. Under these conditions, the performance of a multi-process system where multiple processes share various resources can be enhanced by monitoring and controlling the relationship between the user processes and the system resources. This paper applies object oriented concept to the performance management and suggests a standard for the management. Resource managers and user processes are defined as managed object and a performance manager is defined as a managing object. A protocol between the user processes and performance manager is designed and attributes and methods of the objects are also defined. Through the standardization, the user processes and the performance manager can be developed independently and the system's performance can also be collectively managed.

• Culinary science and hospitality research
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• v.20 no.1
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• pp.1-17
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• 2014

Under the needs to study the predictors of the frontline employees' service-oriented organizational citizenship behaviors(OCBs) in the hotel industry, this study aimed to the influence of goal orientations on the OCBs. The two factors of performance goal and learning goal orientations were hypothesized to influence each dimension of OCBs(loyalty, service delivery, and participation). The data from 266 five star deluxe hotel employees were analyzed with descriptive statistics, multi-variate analysis of variance, and structural equation modeling conducted using SPSS 19.0 and AMOS 20.0. The results showed learning goal orientation positively influenced all dimensions of the OCBs while performance goal orientation positively influenced all dimensions except loyalty. These results suggest that hotel practitioners need to seek the applicants who are willingly oriented to specific goals at recruiting process. Furthermore, hotel organizations need to utilize the employees' goal approach to motivate their performances.

• Therapeutic Science for Rehabilitation
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• v.3 no.1
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• pp.67-77
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• 2014

Objective : The purpose of this study was to examine task-oriented training affects on instrumental activity of daily living for elderly with dementia. Methods : The participant is a 75 years old female with dementia. The intervention was performed for 45 minute on 3 times per week over 1 month. Independent variable was task-oriented training and dependent variable were memory(DST), executive function(TMT-A, CDT), changing of IADL(AMPS). Results : The results showed that the participant significantly improved in executive function, performance of IADL. However, the participant did not show significant improvement in memory. Conclusion : In conclusion, the findings of this study indicate that task-oriented training is positive effect on performance of IADL in dementia.

• Journal of the Korea Society of Computer and Information
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• v.14 no.9
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• pp.1-10
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• 2009

The field of the web service orchestration introduced to generate a valuable service by reusing single services. Recently, it suggests rule-based searching and composition by the AI (Artificial Intelligence) instead of simple searching or orchestration based on the IOPE(Input, Output, Precondition, Effect) to implement the Semantic web as the web service of the next generation. It introduce a AOP programming paradigm from existing object-oriented programming paradigm for more efficient modularization of software. In this paper, we design a dynamic web service orchestration and invocation scheme applying Aspect-Oriented Programming (AOP) and Reflection for Semantic web. The proposed scheme makes use of the Reflection technique to gather dynamically meta data and generates byte code by AOP to compose dynamically web services. As well as, our scheme shows how to execute composed web services through dynamic proxy objects generated by the Reflection. For performance evaluation of the proposed scheme, we experiment on search performance of composed web services with respect to business logic layer and user view layer.

• Journal of Electrical Engineering and Technology
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• v.6 no.2
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• pp.226-232
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• 2011

The $H_{\infty}$ approach, adopted in this paper, is based on loop shaping using a normalized coprime factor combined with a field-oriented control to control induction motor. We develop two loops. The first one, the inner loop, controls the stator current by $H{\infty}$ controller in order to obtain good performance. The second loop, the outer one, guarantees stability and tracking performance of speed and rotor flux using a proportional integral controller. When the rotor flux cannot be measured, we introduce a flux observer to estimate the rotor flux. Simulation and experimental results are presented to validate the effectiveness and the good performance of this control technique.

• The Journal of the Acoustical Society of Korea
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• v.16 no.1E
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• pp.57-63
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• 1997

In this paper, we investigated performance of a vocabulary-independent speech recognizer with speaker adaptation. The vocabulary-independent speech recognizer does not require task-oriented speech databases to estimate HMM parameters, but adapts the parameters recursively by using input speech and recognition results. The recognizer has the advantage that it relieves efforts to record the speech databases and can be easily adapted to a new task and a new speaker with different recognition vocabulary without losing recognition accuracies. Experimental results showed that the vocabulary-independent speech recognizer with supervised offline speaker adaptation reduced 40% of recognition errors when 80 words from the same vocabulary as test data were used as adaptation data. The recognizer with unsupervised online speaker adaptation reduced abut 43% of recognition errors. This performance is comparable to that of a speaker-independent speech recognizer trained by a task-oriented speech database.