• Journal of Korea Society of Industrial Information Systems
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• v.14 no.4
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• pp.30-36
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• 2009

In this paper, we develop the next generation mobile system based on SBC(Server Based Computing). SBC is one of the popular topic and only one server system is used as multiple personal systems with a terminal, a monitor and a keyboard. The advantages of this system are easy-upgrade, low costs and convenience for each user. But it is difficult to design and manufacture the multimedia streaming system and devices control system for external devices. In this paper, we represent and develops the Mobile system based on SBC and the test performances shows that our system has good performances of multimedia system and security for internet.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.156-157
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• 2011

In this work, we study the checkpoint/restart problem for message-passing parallel applications running on cloud computing environment. This is a new direction which arises from the trend of enabling the applications to run on the cloud computing environment. The main objective is to propose an efficient checkpoint algorithm for message-passing parallel applications considering communications with external systems. We further implement the novel algorithm by modifying gSOAP and OpenMPI (the open source libraries) which support service calls and checkpoint message-passing parallel programs, especially. The simulation showed that additional costs to the executing and checkpointing application of the algorithm are negligible. Ultimately, the algorithm supports efficiently the checkpoint/restart service for message-passing parallel applications, that send requests to external services.

• Proceedings of the Korean Society of Computer Information Conference
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• 2013.07a
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• pp.315-316
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• 2013

근 스마트폰 보급률이 높아짐에 따라 스마트폰을 활용한 다양한 어플리케이션들이 있다. 이러한 스마트폰 어플리케이션을 클라우드 컴퓨팅 활용하여 구현할 경우, 클라우드에서 서버를 임대하여 사용한 만큼 비용을 지불할 수 있다. 따라서 서버 과부화에 대한 서비스 가용성을 보장할 수 있으며 네트워크 및 자원 사용량을 모니터링할 수 있다. 또한, 사용한 만큼 지불하는 방식이기 때문에 운영비용에 대한 부담이 줄어들 수 있다.

• Journal of the Korean Operations Research and Management Science Society
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• v.9 no.2
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• pp.15-22
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• 1984

A deterministic multiproduct, facility-in series multiperiod production planning model is analyzed, where each period demand for the product of a facility appear in a fixed proportion of that for the product of the immediately following facility. The model considers concave production and inventory costs, which can depend upon the production in different facilities. No backlogging is allowed. It is shown that the model is represented via a single source network, which facilitates development of efficient dynamic programming algorithms for computing the optimal production schedule.

• IE interfaces
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• v.8 no.2
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• pp.151-159
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• 1995

Two-dimensional cutting stock problem is to find a waste-minimizing method of cutting a single rectangular plane into a number of smaller pieces of known dimensions. In practice, besides wastes, setup cost taken during adjusting is of an important concern. We suggest 2-phased guillotine cutting method as a solution to the problem which minimize wastes and setup costs. Also, in order to reduce the computing time we apply techniques of discretization, cutoff, median. Experimental results show good performance of our algorithm.

• The Journal of Society for e-Business Studies
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• v.17 no.1
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• pp.111-136
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• 2012

The global recession has made it more difficult for companies to invest in IT, and they are increasingly aware of the environmental costs of so doing. In these circumstances, cloud computing has emerged as a new paradigm in the business IT sector. Governments, institutes and companies around the world, as well as specifically in Korea since 2009, have turned to this model of providing IT resources. This study is concerned to identify those characteristics of cloud computing that affect its introduction on a company's part; it offers a theoretical framework describing cloud services and seeks to establish causal linkages between antecedent factors and a company's introduction and application of this form of IT provision. The features of cloud computing in particular contexts that the study selected for analysis were its scalability, speed, security, potential compatibility with existing services, efficiency, economic feasibility, dependency and credibility. The study thus related these to whether or not cloud computing was adopted, verifying adjustment effects for cloud services. On the basis of a survey of enterprise IT decision-makers, it emerged through a statistical analysis of correlations that cloud computing's efficiency, economic feasibility and credibility had an effect on its introduction. This study's results should be of use to vendors and potential purchasers of cloud computing services. It is one of the first pieces of research on cloud computing from the customer perspective, based on the perceived characteristics of cloud services as they are seen and valued by users.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.675-677
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• 2013

IT ecosystem is changing with the spread of smart devices and thus, cloud computing fields have been issued to companies. Cloud computing reduces IT costs and aims for eco-friendly Green IT. It also supports all kinds of IT equipment so you can conduct business in real time when moving. With these advantages, many corporations are considering cloud computing but there are security issues when implementing cloud. In this paper, we analyze security problems of clouding service and present the appropriate guidelines. This will be utilized in the fields of cloud computing and service delivery.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.4
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• pp.1147-1161
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• 2023

The Internet of Things (IoT) requires a new processing model that will allow scalability in cloud computing while reducing time delay caused by data transmission within a network. Such a model can be achieved by using resources that are closer to the user, i.e., by relying on edge computing (EC). The amount of IoT data also grows with an increase in the number of IoT devices. However, building such a flexible model within a heterogeneous environment is difficult in terms of resources. Moreover, the increasing demand for IoT services necessitates shortening time delay and response time by achieving effective load balancing. IoT devices are expected to generate huge amounts of data within a short amount of time. They will be dynamically deployed, and IoT services will be provided to EC devices or cloud servers to minimize resource costs while meeting the latency and quality of service (QoS) constraints of IoT applications when IoT devices are at the endpoint. EC is an emerging solution to the data processing problem in IoT. In this study, we improve the load balancing process and distribute resources fairly to tasks, which, in turn, will improve QoS in cloud and reduce processing time, and consequently, response time.

• Environmental and Resource Economics Review
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• v.22 no.3
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• pp.499-520
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• 2013

This study proposes an iterative approach to the estimation of the marginal abatement costs of undesirable outputs by computing the slope of the efficient production possibilities frontier on the basis of the efficient projection points generated by the directional output distance function approach due to Fare et al. (2005) based on duality theory. In case of the latter methodology, the estimated marginal abatement costs differ significantly depending on the choice of the directional output vector. In addition, depending on the curvature of the underlying PPF the efficient projection points may be located at a significant distance away from their actually observed counterparts. While it would be more logical to estimate marginal abatement costs as a PPF slope at a point corresponding to the actually observed emissions level, the methodology based on duality theory is likely to produce unstable results due to the problems associated with applying the theorem of implicit function differentiation. Since our methodology is not based on duality theory, our results are immune to both of these problems. We apply our methodology to a sample of Western European countries for the period of 1995-2011 to illustrate our approach.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.12
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• pp.913-917
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• 2009

Flash memories have asymmetric I/O costs for read and write in terms of latency and energy consumption. However, the ratio of these costs is dependent on the type of storage. Moreover, it is becoming more common to use two flash memories on a system as an internal memory and an external memory card. For this reason, buffer cache replacement algorithms should consider I/O costs of device as well as possibility of reference. This paper presents WWCLOCK(Write-Weighted CLOCK) algorithm which directly uses I/O costs of devices along with recency and frequency of cache blocks to selecting a victim to evict from the buffer cache. WWCLOCK can be used for wide range of storage devices with different I/O cost and for systems that are using two or more memory devices at the same time. In addition to this, it has low time and space complexity comparable to CLOCK algorithm. Trace-driven simulations show that the proposed algorithm reduces the total I/O time compared with LRU by 36.2% on average.