• 한국군사과학기술학회지
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• 제17권5호
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• pp.703-710
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• 2014

An Image-Based Target Tracker maintains LOS(Line Of Sight) to a target by controlling azimuth and elevation gimbals of an ISS(Inertially Stabilized System). Its controller produces the gimbals commands of the ISS using tracking errors provided by an image tracker. The control performance of the target tracker with PI controller generally used for tracking controller is limited because of bandwidth limitation by time delay yielded by image capture and processing of the image tracker. In this paper, tracking controller using target states estimator is proposed which can enhance the tracking performance under the highly dynamic maneuvering conditions of the ISS and the target. Simulation results show that the proposed method can improve the tracking performance than that with only PI controller.

• 한국군사과학기술학회지
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• 제21권3호
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• pp.396-402
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• 2018

Earned Value Management(EVM) has been used to manage and forecast defense project schedule and cost over the last two decades in the world. However to support the lacking ability of schedule analysis in traditional EVM, earned schedule(ES) has been introduced as a tool to more accurately estimate schedule performance. This paper compares which method EVM or ES, provides more accurate schedule predictors in 32 Korean defense research and development projects. As a result of comparison, the ES method can predict the future schedule more reliably than the EVM method. We also analyze early warning function of schedule performance index considering project duration extension point. Through the analysis results, we confirm that both the EVM and the ES method lack the ability of the early warning in terms of the current schedule management criterion.

• The Journal of Asian Finance, Economics and Business
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• 제7권7호
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• pp.565-575
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• 2020

This study aims to analyze the digital performance of Kazakhstan through dynamic analysis of national statistics and international indices as Global Innovation Index and ICT Development Index. The research combines three stages: analysis of digital transformation policies performance, review of ICT industry development, and comparative analysis of the positions of Kazakhstan, Turkey and South Korea as a benchmark in the international indices. This research findings show that despite great efforts of Kazakhstan in digitalization, the ICT industry contribution does not increase, it even falls. The international indices demonstrate that the reason is the weakness of the country in skills, venture capital, and innovation linkages. This leads to low knowledge, technology outputs, and creative outputs. The enablers of digital and overall innovation advancement of economy are identified. According to the international rankings the country has been doing its best in Access and Use areas. Another enablers are good business environment, ease of starting a business, protecting minority investors, and FDI inflows. The findings help to draw recommendations for strategic directions in order to improve the digital performance in Kazakhstan. The main limitation of this study is a lack of dynamic information on positions of Kazakhstan in other international indices related to digitalization.

• 한국자동차공학회논문집
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• 제22권4호
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• pp.36-45
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• 2014

Model based control methods are widely used to improve the control performance of diesel engine air systems because the control results of the air system significantly affect the emission level and drivability. However, the model based control algorithm requires a lot of unmeasurable states which are hard to be measured in a mass production engine. In this study, an air system model of the diesel engine is proposed to estimate 11 unmeasurable states using only sensors equipped in a mass production engine. In order to improve the estimation performance in the transient condition, dynamic characteristics of the air system are analyzed and implemented as discrete filters. Turbine and compressor efficiency models are also proposed to overcome a limitation of the constant or look-up table based efficiency values. The proposed air system model was validated in steady state and transient conditions by real-time engine experiments. The maximum error of the estimation for 11 physical states was 11.7%.

• 한국병원경영학회지
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• 제14권2호
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• pp.60-74
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• 2009

This study purports to verify managerial effectiveness of the integrated delivery system(IDS) of Japanese health care institutions through comparing the managerial performance between hospital groups providing with both acute and nursing care and those with acute care only. Data on the managerial performance of 697 hospitals providing with nursing care together and 819 hospitals providing with acute care only were collected from Japanese Central Social Insurance Medical Councils 2001, 2003, 2005, and were analyzed using mean comparison test(t-test) between the two groups. The results revealed that there were significant differences between the two groups in such indicators as ratio of material cost, labor cost, depreciation rate, total margin, operating margin, average number of outpatient per day, average revenue of an inpatient per day, total amount of labor cost, gross revenue per employee, and labor productivity. However, we could not find out any consistent evidence which support the effect of integrated delivery system on the hospital managerial performance. Further discussion was made on the limitation of the study and future research agenda relevant to the topic.

• 전력전자학회논문지
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• 제21권1호
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• pp.58-64
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• 2016

This study presents a design method for a single-loop voltage controller that is suitable for an arbitrary waveform generator (AWG). The voltage control algorithm of AWG should ensure high dynamic performance and should attain sufficient robustness to disturbances such as inverter nonlinearity, sensor noise, and load current. By analyzing the power circuit of AWG, control limitation and control target are presented to improve the dynamic performance of AWG. The proposed voltage control algorithm is composed of a single-loop output voltage control, an inverter current feedback term to improve transient response, and a load current feedforward term to prevent voltage distortion. The guideline for setting control gain is presented based on output filter parameters and digital time delay. The performance of the proposed algorithm is proven by experimental results through comparison with the conventional algorithm.

• Journal of Electrical Engineering and Technology
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• 제12권3호
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• pp.1146-1155
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• 2017

Normally, the artificial intelligence algorithms are widely applied to the optimal controller design. Then, it is expected that the best output performance is achieved. Unfortunately, when resulting controller parameters are implemented by using the practical devices, the output performance cannot be the best as expected. Therefore, the paper presents the optimal controller design using the combination between the state-space averaging model and the adaptive Tabu search algorithm with the new criteria as two penalty conditions to handle the mentioned problem. The buck-boost converter regulated by the cascade PI controllers is used as the example power system. The results show that the output performance is better than those from the conventional design method for both input and load variations. Moreover, it is confirmed that the reported controllers can be implemented using the realistic devices without the limitation and the stable operation is also guaranteed. The results are also validated by the simulation using the topology model of MATLAB and also experimentally verified by the testing rig.

• 한국군사과학기술학회지
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• 제21권2호
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• pp.158-165
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• 2018

Recently there is a great interest in the bi-static sonar. However, since the transmitter and the receiver operate on different platforms, it may be necessary to operate the system in a non-cooperative mode. In this situation, the detection and localization performance are limited. Therefore, it is necessary to classify the received pulse from the transmitter to overcome the performance limitation. In this paper, we proposed a robust automatic pulse classification method that can be applied to real systems. The proposed method eliminates the effects of noise and multipath propagation through post-processing and improves the pulse classification performance. We also verified the proposed method through the sea experimental data.

• 한국통신학회논문지
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• 제28권4B호
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• pp.339-350
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• 2003

인터넷이 급성장하면서 망 사용자들은 대역폭의 증가라는 양적인 측면 외에도 서비스 품질의 개선과 보장이라는 질적인 측면까지 요구하게 되었다. 점점 더 망의 기능성이 강조됨에 따라 망 장비의 성능과 기능도 중요하게 여겨지고 있는데, 특히 에지 라우터는 고성능, 다기능, 유연성이 모두 요구되는 시스템이다. 이러한 특성의 시스템 설계를 위해 최근 고려되고 있는 방법이 네트워크 프로세서를 사용하는 것이다. 본 논문에서는 ASIC의 고성능과 소프트웨어 기반의 유연성을 모두 제공하는 네트워크 프로세서를 사용하여 에지 급의 MPLS 라우터를 개발하고, 그 결과를 기반으로 네트워크 프로세서의 향후 적용가능성을 살펴본다.

• Journal of Information Processing Systems
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• 제13권4호
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• pp.731-751
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• 2017

The burgeoning distribution of smartphone web applications based on various mobile environments is increasingly focusing on the performance of mobile applications implemented by JavaScript and HTML5 (Hyper Text Markup Language 5). If application software has a simple functional processing structure, then the problem is benign. However, browser loads are becoming more burdensome as the amount of JavaScript processing continues to increase. Processing time and capacity of the JavaScript in current mobile browsers are limited. As a solution, the Web Worker is designed to implement multi-threading. However, it cannot guarantee the computing ability as a native application on mobile devices, and is not sufficient to improve processing speed. The method proposed in this research overcomes the limitation of resources as a mobile client and guarantees performance by native application software by providing high computing service. It shifts the JavaScript process of a mobile device on to a cloud-based computer server. A performance evaluation experiment revealed the proposed algorithm to be up to 6 times faster in computing speed compared to the existing mobile browser's JavaScript process, and 3 to 6 times faster than Web Worker. In addition, memory usage was also less than the existing technology.