• Proceedings of the KSME Conference
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• 2001.06a
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• pp.447-452
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• 2001

An automated system is developed to perform fatigue crack growth tests under constant effective stress intensity factor range ${\Delta}K_{eff}$. In the system, crack length and crack opening load are measured in real-time by using the unloading elastic compliance method. The system consists of two personal computers, an analogue electrical subtraction circuit, a stepping motor, a stepping motor driver, a PIO board, and the application software used to integrate the whole system. The performance of the developed system was tested and discussed performing constant ${\Delta}K_{eff}$ crack growth tests on a CT specimen of 7075-T6 aluminum alloy. The performance of the system is found to be strongly dependent on the accuracy of measurements of crack opening load. Besides constant ${\Delta}K_{eff}$ testing, the system is expected to be successfully applied for automation of various fatigue tests.

• Journal of Trauma and Injury
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• v.23 no.2
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• pp.157-162
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• 2010

Purpose: Free flap reconstruction in the pediatric population is difficult. However, microsurgery has had remarkable success rates in children. The aim of study is to present our clinical experience using free flap for reconstruction of soft tissue defects in children and to describe long-term follow-up results. Methods: Between June 2002 and July 2010, 30 cases of pediatric reconstruction were performed with free flap. The authors analyzed several items, such as the kind of flap, associated complications, and growth problems. Results: Among the 30 cases, 21 cases were due to traffic accidents, 5 to cancer, and 4 to falls and other soft tissue defects. The lower leg and foot were the most common sites of the lesion. In the free flap operations we have done, 20 cases involved an anterolateral thigh perforator free flap, 6 a superficial circumflex iliac perforator free flap, and 4 an upper medial thigh perforator free flap. In early postoperative complications, partial necrosis was seen in 2 cases, infection in 1 case, and the hematoma in 1 case. A satisfactory success rate and functional results were achieved. Conclusion: Free flap reconstruction in children allows satisfactory function with no significant effect on growth. Free flaps are regarded as the primary choice for selective pediatric reconstructive cases.

• Journal of Internet Computing and Services
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• v.20 no.6
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• pp.21-28
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• 2019

Process mining is state-of-the-art technology in the workflow field. Recently, process mining becomes more important because of the fact that it shows the status of the actual behavior of the workflow model. However, as the process mining get focused and developed, the material of the process mining - workflow event log - also grows fast. Thus, the process mining algorithms cannot operate with some data because it is too large. To solve this problem, there should be a lightweight process mining algorithm, or the event log must be divided and processed partly. In this paper, we suggest a set of operations that control and edit XES based event logs for process mining. They are designed based on relational algebra, which is used in database management systems. We designed three operations for tailoring XES event logs. Select operation is an operation that gets specific attributes and excludes others. Thus, the output file has the same structure and contents of the original file, but each element has only the attributes user selected. Union operation makes two input XES files into one XES file. Two input files must be from the same process. As a result, the contents of the two files are integrated into one file. The final operation is a slice. It divides anXES file into several files by the number of traces. We will show the design methods and details below.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.1124-1126
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• 1997

The Unified Power Flow Controller(UPFC) with a series inverter and a shunt inverter ia able to control all three line Parameters(voltage, impedance and phase angle) and so UPFC technology has the potential to enhance the implementation and broad application of the FACTS concept with improved Performance. In this Paper, the UPFC is applied in order to improve the power flow oscillation damping. The modal performance measure is minimized in order to determine the optimal parameters of UPFC controller for damping Power flow oscillations. The dynamics of the injected voltage of UPFC is represented as a first order delay element. The UPFC controller used here is of the PIO type and the input signal to the controller is the active power flow through the UPFC. The effect of UPFC application to the Power system are analyzed from the stand point of power system oscillation damping.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10b
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• pp.1113-1116
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• 2000

기존의 연구에서는 셀룰러 망에서 호 수락 제어 시에 다음 두 가지 요소를 고려하지 않는다. 첫 번째 요소는 각각의 셀, 특히 micro/pio 셀에서 서비스 제공이다. micro/pico 셀과 같이 심한 트래픽 변동이 있는 셀에서는 호 단절률이 수렴할 수 없기 때문에 이동 QoS와 서비스 제공이 불가능하다. 두 번째 요소는 망에서 호를 수용할 수 있는 능력과 관련 있는 GOS 이다. 일반적으로 여러 비율의 서비스는 서비스의 집합으로 특정지을 수 있고, 각각의 것들은 다른 양의 대여폭을 요구한다. 이질적인 멀티미디어 서비스 클래스를 가진 망에서는 소수의 광대역호가 망 자원의 대부분을 점유해서, 신규호에 대한 봉쇄로 망 성능을 떨어뜨릴 수 있다 그래서, GoS는 광대역호 제어에 의해서 향상될 수 있다. 본 논문에서는 이동 트래픽 조건에서 서비스 제공이 가능한 셀들의 최소 집합이면서 논리적인 단위인 지역이라고 불리는 새로운 개념을 소개한다. 그리고 서비스 제공 단위가 셀보다는 지역단위로 한 경우에 성능이 더 좋고 GoS 를 향상시킬 수 있는 방법인 지역기반 CAC 를 제한한다. 마지막으로 시뮬레이션에서는 QoS와 GoS 관점에서 RCAC가 현재까지 제안된 다른 방법보다 더 좋은 성능을 제공한다는 것을 보여준다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.8
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• pp.4108-4122
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• 2019

Workflow process mining is becoming a more and more valuable activity in workflow-supported enterprises, and through which it is possible to achieve the high levels of qualitative business goals in terms of improving the effectiveness and efficiency of the workflow-supported information systems, increasing their operational performances, reducing their completion times with minimizing redundancy times, and saving their managerial costs. One of the critical challenges in the workflow process mining activity is to devise a reasonable approach to discover and recognize the bottleneck points of workflow process models from their enactment event histories. We have intuitively realized the fact that the iterative process pattern of redo-activities ought to have the high possibility of becoming a bottleneck point of a workflow process model. Hence, we, in this paper, propose an algorithmic approach and its implementation to discover the redo-activities and their performers' involvements patterns from workflow process enactment event logs. Additionally, we carry out a series of experimental analyses by applying the implemented algorithm to four datasets of workflow process enactment event logs released from the BPI Challenges. Finally, those discovered redo-activities and their performers' involvements patterns are visualized in a graphical form of information control nets as well as a tabular form of the involvement percentages, respectively.

• Journal of Internet Computing and Services
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• v.20 no.3
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• pp.85-92
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• 2019

In this paper, we extract the quantitative relation data of activities from the workflow event log file recorded in the XES standard format and connect them to rediscover the workflow process model. Extract the workflow process patterns and proportions with the rediscovered model. There are four types of control-flow elements that should be used to extract workflow process patterns and portions with log files: linear (sequential) routing, disjunctive (selective) routing, conjunctive (parallel) routing, and iterative routing patterns. In this paper, we focus on four of the factors, disjunctive routing, and conjunctive path. A framework implemented by the authors' research group extracts and arranges the activity data from the log and converts the iteration of duplicate relationships into a quantitative value. Also, for accurate analysis, a parallel process is recorded in the log file based on execution time, and algorithms for finding and eliminating information distortion are designed and implemented. With these refined data, we rediscover the workflow process model following the relationship between the activities. This series of experiments are conducted using the Large Bank Transaction Process Model provided by 4TU and visualizes the experiment process and results.

• Journal of Internet Computing and Services
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• v.20 no.2
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• pp.101-108
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• 2019

Workflow management systems (WfMSs) automate and manage workflows, which are implementations of organizational processes operated in process-centric organizations. In this paper, wepropose an algorithm to discover temporal work transference networks from workflow execution logs. The temporal work transference network is a special type of enterprise social networks that consists of workflow performers, and relationships among them that are formed by work transferences between performers who are responsible in performing precedent and succeeding activities in a workflow process. In terms of analysis, the temporal work transference network is an analytical property that has significant value to be analyzed to discover organizational knowledge for human resource management and related decision-making steps for process-centric organizations. Also, the beginning point of implementinga human-centered workflow intelligence framework dealing with work transference networks is to develop an algorithm for discovering temporal work transference cases on workflow execution logs. To this end, we first formalize a concept of temporal work transference network, and next, we present a discovery algorithm which is for the construction of temporal work transference network from workflow execution logs. Then, as a verification of the proposed algorithm, we apply the algorithm to an XES-formatted log dataset that was released by the process mining research group and finally summarize the discovery result.

• Journal of Internet Computing and Services
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• v.20 no.5
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• pp.49-55
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• 2019

Organizations design and operate business process models to achieve their goals efficiently and systematically. With the advancement of IT technology, the number of items that computer systems can participate in and the process becomes huge and complicated. This phenomenon created a more complex and subdivide flow of business process.The process instances that contain workcase and events are larger and have more data. This is an essential resource for process mining and is used directly in model discovery, analysis, and improvement of processes. This event log is getting bigger and broader, which leads to problems such as capacity management and I / O load in management of existing row level program or management through a relational database. In this paper, as the event log becomes big data, we have found the problem of management limit based on the existing original file or relational database. Design and apply schemes to archive and analyze large event logs through Hadoop, an open source distributed file system, and HBase, a NoSQL database system.

• Archives of Plastic Surgery
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• v.50 no.1
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• pp.130-140
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• 2023

Microsurgery, which deservedly sits on top of the reconstruction ladder, has been a boon to plastic surgery. It is because of this marvelous tool that plastic surgeons the world over have been able to tackle many reconstructive dilemmas, which were once considered to be an improbability. Microsurgery-aided revolutions have rendered a new meaning to all forms of reconstruction-whether it is postoncological, posttraumatic, or postlymphedema reconstruction. As the most advanced reconstructive medium at our disposal that has broadened the horizons of plastic surgery exponentially, it is but obvious that many budding plastic surgeons are drawn toward this subspecialty. In lieu of the aforementioned facts, it is necessary to sensitize all such aspiring surgeons about the various intricacies concerning the field of microsurgery. This article with its focus on the six desirable microsurgical attributes of "Clarity, Curiosity, Perseverance, Passion, An Open Mindset and Action," is meant to be a modest attempt on part of the authors to share their microsurgical insights, procured through their respective journeys, with budding aspirants, hoping to sensitize as well as motivate them for the challenging path that lies ahead.