• Journal of Korea Water Resources Association
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• v.42 no.3
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• pp.213-225
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• 2009

A stationary Markov chain model is a stochastic process with the Markov property. Having the Markov property means that, given the present state, future states are independent of the past states. The Markov chain model has been widely used for water resources design as a main tool. A main assumption of the stationary Markov model is that statistical properties remain the same for all times. Hence, the stationary Markov chain model basically can not consider the changes of mean or variance. In this regard, a primary objective of this study is to develop a model which is able to make use of exogenous variables. The regression based link functions are employed to dynamically update model parameters given the exogenous variables, and the model parameters are estimated by canonical correlation analysis. The proposed model is applied to daily rainfall series at Seoul station having 46 years data from 1961 to 2006. The model shows a capability to reproduce daily and seasonal characteristics simultaneously. Therefore, the proposed model can be used as a short or mid-term prediction tool if elaborate GCM forecasts are used as a predictor. Also, the nonstationary Markov chain model can be applied to climate change studies if GCM based climate change scenarios are provided as inputs.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.499-499
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• 2018

Hydro-meteorological extremes are trivial in these days. Therefore, it is important to identify extreme hydrological events in advance to mitigate the damage due to the extreme events. In this context, exploring temporal distribution of sub-daily extreme rainfall at multiple rain gauges would informative to identify different states to describe severity of the disaster. This study proposehidden Markov chain model (HMM) based rainfall analysis tool to understand the temporal sub-daily rainfall patterns over South Korea. Hourly and daily rainfall data between 1961 and 2017 for 92 stations were used for the study. HMM was applied to daily rainfall series to identify an observed hidden state associated with rainfall frequency and intensity, and further utilized the estimated hidden states to derive a temporal distribution of daily extreme rainfall. Transition between states over time was clearly identified, because HMM obviously identifies the temporal dependence in the daily rainfall states. The proposed HMM was very useful tool to derive the temporal attributes of the daily rainfall in South Korea. Further, daily rainfall series were disaggregated into sub-daily rainfall sequences based on the temporal distribution of hourly rainfall data.

• Journal of Arbitration Studies
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• v.34 no.1
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• pp.75-101
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• 2024

"ESG management" guides companies to prioritize corporate social responsibility and sustainable development as key management objectives, going beyond mere financial performance pursuits. This approach involves creating a sustainable and robust supply chain by urging companies, acting as 'supply chain managers', to implement ESG management practices alongside their 'supply chain partners'. The domestic business community has been quick to respond to this trend, recognizing that failure to adhere to ESG standards set by organizations such as the EU and SEC could lead to severe repercussions, including exclusion from international trade and reputational damage. POSCO and NAVER, two leading Korean companies, are at the forefront of practicing ESG management effectively. They have both produced and publicly disclosed ESG management reports, showcasing their success in enhancing supply chain ESG management. However, as supply chain managers enforce ESG-related obligations on their suppliers, the likelihood of disputes between the parties may increase. In scenarios where supply chain ESG management leads to conflicts between supply chain managers and suppliers, commercial arbitration emerges as a viable solution for dispute resolution. This method offers several advantages, including the arbitrators' expertise, time and cost efficiency, the binding nature of decisions akin to a court's final judgment, international recognition under the New York Convention, confidentiality, and ample opportunity for parties to be heard. Our analysis focuses on the emerging disputes between supply chain managers and suppliers within the context of supply chain ESG management, particularly examining the cases of POSCO and NAVER. By categorizing the expected types of disputes and assessing the appropriateness of commercial arbitration for their resolution, we highlight the effectiveness of this approach. Furthermore, we propose leveraging the Korean Commercial Arbitration Board's role to enhance the use of arbitration in resolving supply chain ESG disputes, underscoring its potential as a strategic tool for maintaining sustainable and harmonious supply chain relationships.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.2
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• pp.102-111
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• 2000

Methodology of volumetric error identification and compensation is presented to improve the accuracy of NC machine tools by using a reference artifact and a touch trigger probe. Homogeneous transformation matrix and kinematic chain are used for modeling the geo-metric and thermal errors of a three-axis vertical machining center. The reference artifact is designed and fabricated to identify the model parameters by machine tool metrology. Parameters in the error model are able to be identified and updated by direct measurement of the reference artifact on the machine tool under the actual conditions which include the thermal interactions of error sources. A volumetric error compensation system based on IBM/PC is linked with a FANUC CNC controller to compensate for the identified volumetric error in machining workspace.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.12
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• pp.2899-2908
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• 2000

Methodology of volumetric error identification is presented to improve the accuracy of NC machine tools by using a reference artifact and a touch trigger probe. Homogeneous transformation matrix and kinematic chain are used for modeling the geometric and thermal errors of a three-axis vertical machining center. The reference artifact is designed and fabricated to identify the model parameters by machine tool metrology. Parameters in the error model are able to be identified and updated by direct measurement of the reference artifact on the machine tool under the actual conditions which include the thermal interactions of error sources. The proposed method can speed up and simplify volumetric error identification processes.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.650-653
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• 2014

기존의 소프트웨어 개발은 SW품질을 중요시 하지만, 고품질에 대한 문제가 아직도 존재한다. 또한 기존 레가시 시스템는 개발자나 설계의 부재 경우가 많고, 코드의 내부 복잡도와 모듈간의 결합도가 높을 가능성이 높다. 따라서 코드 가시화를 통한 복잡도 개선은 고품질화과 더불어 코드 모듈의 재사용과 유지보수등과 직접적 관련성이 있다. 본 논문은 기존 SW가시화용 자동 Tool Chain 기반에서 여러 리펙토링 방법 절차 적용으로 복잡도 개선을 제안 한다. 이런 코드 가시화가 결과적으로 타깃의 결합도를 줄일 수 있다. 기존의 레가시 코드에 자동 Tool chain적용은 고품질 적용이 충분히 예상된다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.422-427
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• 2006

This paper presents force-feedback control performance of a haptic device in virtual environment of minimally invasive surgery(MIS). As a first step, based on an electrorheological(ER) fluid and spherical geometry, a new type of master device is developed and integrated with a virtual environment of MIS such as a surgical tool and human organ. The virtual object is then mathematically formulated by adopting the shape retaining chain linked(S-Chain) model. After evaluating reflection force, computational time, and compatibility with real time control, the virtual environment of MIS is formulated by interactivity with the ER haptic device in real space. Tracking control performances for virtual force trajectory are presented in time domain, and theirtrackingerrorsareevaluated.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.12 s.117
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• pp.1286-1293
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• 2006

This paper presents force-feedback control performance of a haptic device in virtual environment of minimally invasive surgery(MIS). As a first step, based on an electrorheological (ER) fluid and spherical geometry, a new type of master device is developed and integrated with a virtual environment of MIS such as a surgical tool and human organ. The virtual object is then mathematically formulated by adopting the shape retaining chain linked(S-chain) model. After evaluating reflection force, computational time, and compatibility with real time control, the virtual environment of MIS is formulated by interactivity with the ER haptic device in real space. Tracking control performances for virtual force trajectory are presented in time domain.

• Journal of the Korean Society of Physical Medicine
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• v.14 no.1
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• pp.131-138
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• 2019

PURPOSE: This study examined the effects on muscle activation and ankle instability following sudden ankle inversion of the closed kinetic chain exercise using visual feedback to evaluate chronic ankle instability in adult males. METHODS: In this study, 28 subjects with chronic ankle instability were recruited and randomly divided into a closed kinetic chain exercise using a visual feedback group(n=13) and an open kinetic chain exercise group(n=15). Each group underwent 30 minutes of exercise three times a week for 8 weeks. The electromyographic(EMG) values of the rectus femoris, biceps femoris, tibialis anterior, peroneus longus, peroneus brevis, and lateral gastrocnemius muscles were measured to analyze muscle activity. The Cumberland ankle instability tool(CAIT) was used to measure ankle instability. RESULTS: Both groups showed improvements in tibialis anterior, peroneus longus and CAIT score(p<.05). In the experimental group, there were significant improvements in the rectus femoris, biceps femoris, and lateral gastrocnemius muscle activation(p<.05). CONCLUSION: The results suggest that closed kinetic chain exercise using visual feedback can be a useful treatment method for patients with chronic ankle instability.

• Journal of the military operations research society of Korea
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• v.31 no.1
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• pp.73-92
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• 2005

The SCOR(supply chain operations reference) model which is a management tool, has been developed to describe the business activities associated with all phases of satisfying a customer's demand. The model is able to successfully describe and provide a basis for supply chain improvement. In this paper, we review the SCOR model, the present status of the Korean defense logistics system, and suggest an application of the model for the integrated defense logistics system.