• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권4호
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• pp.1911-1930
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• 2017

Overlay routing has emerged as a promising approach to improve reliability and efficiency of the Internet. The key to overlay routing is the placement and maintenance of the overlay infrastructure, especially, the selection and placement of key relay nodes. Spurred by the observation that a few relay nodes with high betweenness centrality can provide more optimal routes for a large number of node pairs, we propose a resilient routing overlay network construction method by introducing Super-Relay nodes. In detail, we present the K-Minimum Spanning Tree with Super-Relay nodes algorithm (SR-KMST), in which we focus on the selection and connection of Super-Relay nodes to optimize the routing quality in a resilient and scalable manner. For the simultaneous path failures between the default physical path and the overlay backup path, we also address the selection of recovery path. The objective is to select a proper one-hop recovery path with minimum cost in path probing and measurement. Simulations based on a real ISP network and a synthetic Internet topology show that our approach can provide high-quality overlay routing service, while achieving good robustness.

• 한국게임학회 논문지
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• 제16권6호
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• pp.69-78
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• 2016

FPS 게임 속 시가지 맵에서 간판, 현수막, 벽보 등의 옥외광고가 흔히 등장한다. 본 논문은 실제 상권들의 옥외광고를 FPS 게임의 시가지 맵에 자동으로 배치하는 방법을 제안한다. 옥외광고는 실제 제품이나 기업의 광고이며 서버에서 관리된다. 실제 광고가 업데이트 되는 경우 게임 소스를 수정하지 않고도 자동으로 배치된다. 광고의 배치에 있어서 플레이어의 위치와 실제 상권의 위치의 관계, 실제 상점의 서비스 형태 등을 활용한다. 수집한 속성들에 우선순위 점수를 부여하여 높은 순위가 우선적으로 맵에 배치된다. 제안하는 배치 방법은 플레이어의 위치를 기반으로 광고를 배치하므로 친근감 유발과 함께 광고 효과를 높일 수 있다.

• 한국통신학회논문지
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• 제38C권7호
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• pp.563-572
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• 2013

본 논문에서는, 00:00~00:30까지 온라인 영업일자변경 작업 등으로, 일시적으로 중단되는 금융권 온라인 계정계 업무에 대하여, 고객원장의 복제보정 적용으로 서비스가 가능토록하며, 배치작업은 별도의 배치서버에서 수행하고, 원장 업데이트는 Center Cut 또는 온라인 서버로 전송해서 처리된다. 따라서, 온라인 업무를 포함한 모든 금융전산업무의 시뮬레이션 결과, 단 1초도 중단 없이, 각 계정 과목별 온라인 원장의 중요한 시점정보인 00:00분 (전영업일자 원장)에 대하여 배치원장과 백업원장을 안전하게 확보하였다.

• 한국의상디자인학회지
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• 제19권4호
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• pp.75-91
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• 2017

This study investigated how learning motivation affects satisfaction with training and employment services and its performance for participants in government-supported job skill development program of the clothing industry so as to provide fundamental data for developing a training program that fosters professionals and relieves the labor shortage in the clothing industry. 180 copies of questionnaires were statistically analyzed by SPSSWIN 21.0. Most trainees were low-income citizens in their 40s and 50s. They were divided into highly educated or low-educated. The results of the research are as follows: when the trainees were motivated by the goals of getting a certificate or a job, employment service satisfaction levels were influenced meaningfully. Secondly, educational satisfaction levels and occupational ability development also scored highly. Therefore, it is important to strengthen instructors' competency. Instructors must be required to have onsite experience so that they can provide authentic education that can be applied to the work field. The government should establish a compulsory training session for the trainers along with an incentive program so that they can catch up with up-to-date technology and trend. Third, the research shows that supporting business startup and job placement is important. Follow-up management systems should be provided in cooperation with relevant institutions of employment and business startups. Either outsourcing or placement of professional advisors is also needed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권2호
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• pp.312-334
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• 2023

In large-scale computing, cloud computing plays an important role by sharing globally-distributed resources. The evolution of cloud has taken place in the development of data centers and numerous servers across the globe. But the cloud information centers incur huge operational costs, consume high electricity and emit tons of dioxides. It is possible for the cloud suppliers to leverage their resources and decrease the consumption of energy through various methods such as dynamic consolidation of Virtual Machines (VMs), by keeping idle nodes in sleep mode and mistreatment of live migration. But the performance may get affected in case of harsh consolidation of VMs. So, it is a desired trait to have associate degree energy-performance exchange without compromising the quality of service while at the same time reducing the power consumption. This research article details a number of novel algorithms that dynamically consolidate the VMs in cloud information centers. The primary objective of the study is to leverage the computing resources to its best and reduce the energy consumption way behind the Service Level Agreement (SLA)drawbacks relevant to CPU load, RAM capacity and information measure. The proposed VM consolidation Algorithm (PVMCA) is contained of four algorithms: over loaded host detection algorithm, VM selection algorithm, VM placement algorithm, and under loading host detection algorithm. PVMCA is dynamic because it uses dynamic thresholds instead of static thresholds values, which makes it suggestion for real, unpredictable workloads common in cloud data centers. Also, the Algorithms are adaptive because it inevitably adjusts its behavior based on the studies of historical data of host resource utilization for any application with diverse workload patterns. Finally, the proposed algorithm is online because the algorithms are achieved run time and make an action in response to each request. The proposed algorithms' efficiency was validated through different simulations of extensive nature. The output analysis depicts the projected algorithms scaled back the energy consumption up to some considerable level besides ensuring proper SLA. On the basis of the project algorithms, the energy consumption got reduced by 22% while there was an improvement observed in SLA up to 80% compared to other benchmark algorithms.

• Journal of Digestive Cancer Research
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• 제9권2호
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• pp.43-49
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• 2021

Background/Aims: Colonic stenting as a bridge to elective surgery is an alternative for emergency surgery in patients with acute malignant colonic obstruction. However, since its benefits are uncertain, we aimed to establish whether it has better clinical outcomes. Methods: The patients with acute malignant left-sided colon obstruction enrolled from January 2009 to December 2018 in National Health Insurance Service Ilsan Hospital. The patients were enrolled to undergo colonic stenting as a bridge to elective surgery or emergency surgery. The following oncological outcomes were assessed: incidence of complete remission, disease progression, local recurrence, and systemic recurrence. Results: Out of 40 patients, 33 received self-expanding metallic stent (SEMS) as a bridge-to-surgery, and 7 underwent emergency surgery. More stoma was made in case of emergency surgery with statistical significance (p < 0.001). There were no significant differences in complete remission rate in curable left-sided malignant colonic obstruction between SEMS as a bridge-to-surgery and emergency surgery. Complete remission was achieved for 3 patients (42.9%) in the non-stent group and 27 patients (81.8%) in the stent group. There was no statistically significant difference in oncologic outcomes between the two groups (p = 0.069). According to multi-variate analysis, advanced TNM stage, Adjuvant chemotherapy, and SEMS bridge-to-surgery were significantly associated with disease-free survival. Disease-free survival rate differed significantly between the two groups (p = 0.024). Conclusions: SEMS as a bridge-to-surgery might be an effective strategy and reduce stoma formation in acute malignant left-sided colon obstruction.

• 한국전자거래학회:학술대회논문집
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• 한국전자거래학회 2005년도 e-Biz World Conference 2005
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• pp.261-266
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• 2005

Web services provide an effective means to carry out coordinated transactions between multiple, independent business parties. While there are several specific protocols currently being discussed to address the coordination of web services-enabled business transactions, we consider the tentative hold protocol (THP) that allows the placement of tentative holds on business resources prior to actual transactions in order to provide increased flexibility in coordination. In this paper, we present a formal coordination framework for applying THP in conjunction with 2PC to the problem in which service providers independently manage resources and clients seek to acquire the resources from multiple providers as a single atomic transaction. The proposed framework facilitates the performance optimization of THP through effective parameterization with the notion of overhold size and hold duration. The simulation results show that the proposed adaptive approach yields a significant improvement over other non-adaptive policies.

• International Journal of Computer Science & Network Security
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• 제21권11호
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• pp.345-353
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• 2021

Cloud computing represent a new era of computing that's forms through the combination of service-oriented architecture (SOA), Internet and grid computing with virtualization technology. Virtualization is a concept through which every cloud is enable to provide on-demand services to the users. Most IT service provider adopt cloud based services for their users to meet the high demand of computation, as it is most flexible, reliable and scalable technology. Energy based performance tradeoff become the main challenge in cloud computing, as its acceptance and popularity increases day by day. Cloud data centers required a huge amount of power supply to the virtualization of servers for maintain on- demand high computing. High power demand increase the energy cost of service providers as well as it also harm the environment through the emission of CO₂. An optimization of cloud computing based on energy-performance tradeoff is required to obtain the balance between energy saving and QoS (quality of services) policies of cloud. A study about power usage of resources in cloud data centers based on workload assign to them, says that an idle server consume near about 50% of its peak utilization power [1]. Therefore, more number of underutilized servers in any cloud data center is responsible to reduce the energy performance tradeoff. To handle this issue, a lots of research proposed as energy efficient algorithms for minimize the consumption of energy and also maintain the SLA (service level agreement) at a satisfactory level. VM (virtual machine) consolidation is one such technique that ensured about the balance of energy based SLA. In the scope of this paper, we explore reinforcement with fuzzy logic (RFL) for VM consolidation to achieve energy based SLA. In this proposed RFL based active VM consolidation, the primary objective is to manage physical server (PS) nodes in order to avoid over-utilized and under-utilized, and to optimize the placement of VMs. A dynamic threshold (based on RFL) is proposed for over-utilized PS detection. For over-utilized PS, a VM selection policy based on fuzzy logic is proposed, which selects VM for migration to maintain the balance of SLA. Additionally, it incorporate VM placement policy through categorization of non-overutilized servers as- balanced, under-utilized and critical. CloudSim toolkit is used to simulate the proposed work on real-world work load traces of CoMon Project define by PlanetLab. Simulation results shows that the proposed policies is most energy efficient compared to others in terms of reduction in both electricity usage and SLA violation.

• 한국비블리아학회지
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• 제21권2호
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• pp.39-56
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• 2010

이 연구는 공공도서관 청소년 프로그램의 현황을 조사하여 문제점을 분석하고 개선 과제를 탐색하였다. 1개 특별시와 6개 광역시의 공공도서관 중 2009년 8월 31부터 9월 4일까지 청소년 프로그램이 실시된 86개관을 대상으로 조사하였다. 이 연구에서는 청소년프로그램을 참여형, 체험형, 강좌형, 콘테스트형, 기관협력형 등 5가지 유형으로 구분하여 각 유형별 특성과 문제점을 분석하였다. 그리고 공공도서관의 청소년 프로그램의 활성화를 저해하는 제반 환경적 문제를 점검하고 발전 방안을 제안하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권11호
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• pp.5357-5381
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• 2018

Cloud computing offers a wide range of on-demand resources over the internet. Utility-based resource allocation in cloud data centers significantly increases the number of cloud users. Heavy usage of cloud data center encounters many problems such as sacrificing system performance, increasing operational cost and high-energy consumption. Therefore, the result of the system damages the environment extremely due to heavy carbon (CO2) emission. However, dynamic allocation of energy-efficient resources in cloud data centers overcomes these problems. In this paper, we have proposed Energy and Service Level Agreement (SLA) Aware Resource Allocation Heuristic Algorithms. These algorithms are essential for reducing power consumption and SLA violation without diminishing the performance and Quality-of-Service (QoS) in cloud data centers. Our proposed model is organized as follows: a) SLA violation detection model is used to prevent Virtual Machines (VMs) from overloaded and underloaded host usage; b) for reducing power consumption of VMs, we have introduced Enhanced minPower and maxUtilization (EMPMU) VM migration policy; and c) efficient utilization of cloud resources and VM placement are achieved using SLA-aware Modified Best Fit Decreasing (MBFD) algorithm. We have validated our test results using CloudSim toolkit 3.0.3. Finally, experimental results have shown better resource utilization, reduced energy consumption and SLA violation in heterogeneous dynamic cloud environment.