• 대한산업공학회지
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• 제35권1호
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• pp.51-57
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• 2009

There are a variety of users and devices in a context-aware computing environment. In this environment, the service provided to a user may be the composition of diverse services rather than one independent service. Before user's devices provide the composite service to the user, they should perceive user's needs by gathering related information segments from other surrounding devices and/or sensors. We consider a context-aware computing environment providing composite and adapted service to users and propose an information processing model that characterizes the device where the collected data should be processed through services and/or applications. Based on this model, we provide an analytical tool to obtain some performance measures of the context-aware computing environment.

• Nuclear Engineering and Technology
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• 제50권1호
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• pp.25-34
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• 2018

The CINDER code has about 60 years of development history, and is thus one of the world's best transmutation computing codes to date. Unfortunately, it is complex and cumbersome to use. Preparing auxiliary input files for activation computation from MCNPX output and executing them using Perl script (activation script) is the first difficulty, and separation of gamma source computing script (gamma script), which analyzes the spectra files produced by CINDER code and creates source definition format for MCNPX code, is the second difficulty. In addition, for highly nonlinear problems, multiple human interventions may increase the possibility of errors. Postprocessing such as making plots with large text outputs is also time consuming. One way to improve these limitations is to make a graphical user interface wrapper that includes all codes, such as MCNPX and CINDER, and all scripts with a visual C#.NET tool. The graphical user interface merges all the codes and provides easy postprocessing of graphics data and Microsoft office tools, such as Excel sheets, which make the CINDER code easy to use. This study describes the VCINDER code (with visual C#.NET) and gives a typical application example.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제26권4호
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• pp.343-352
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• 2022

We present the user-friendly graphical user interface design and implementation of Monte Carlo simulation (MCS) for computing option price of the four-underlying asset step-down equity linked securities (ELS) using the Android platform. The ELS has been one of the most important and influential financial products in South Korea. Most ELS products are based on one-, two-, and three-underlying assets. However, currently there is a demand for higher coupon payment from ELS products because of the increased interest rate in financial market. In order to allow the investors to have higher coupon payment, it is necessary to design a multi-asset ELS such as four-asset step-down ELS. We conduct the computational experiments to demonstrate the performance of the Android platform for pricing four-asset step-down ELS. Furthermore, we perform a comparison test with a three-asset step-down ELS.

• International Journal of Computer Science & Network Security
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• 제23권1호
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• pp.140-146
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• 2023

Resource allocation is one of the top challenges in Internet of Things (IoT) networks. This is due to the scarcity of computing, energy and communication resources in IoT devices. As a result, IoT devices that are not using efficient algorithms for resource allocation may cause applications to fail and devices to get shut down. Owing to this challenge, this paper proposes a novel algorithm for managing computing resources in IoT network. The fog computing devices are placed near the network edge and IoT devices send their large tasks to them for computing. The goal of the algorithm is to conserve energy of both IoT nodes and the fog nodes such that all tasks are computed within a deadline. A bi-partite graph-based algorithm is proposed for stable matching of tasks and fog node computing units. The output of the algorithm is a stable mapping between the IoT tasks and fog computing units. Simulation results are conducted to evaluate the performance of the proposed algorithm which proves the improvement in terms of energy efficiency and task delay.

• International Journal of Computer Science & Network Security
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• 제22권8호
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• pp.35-44
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• 2022

The Internet is extremely important to accomplish numerous items, from education to businesses and entertainment. Therefore, the quality of its performance must be efficient. Nowadays, there is a lack of information available for users to choose a suitable Internet service. What information is available might be insufficient, inaccurate, or regularly updated. Accordingly, there is a need to develop an electronic system that enables users to evaluate their current Internet service subscription. Several factors are used as evaluation criteria in the system that affect users' decisions. In this paper, a prototype of a design science research project is proposed to address a few objectives. First, it can help Internet service users in Saudi Arabia to make the best decision for themselves regarding Internet services subscriptions. Second, it can assist the Saudi government to seek one of the 2030 vision goals: the digital transformation that depends on having a good Internet connection. The proposed solution is a promising one that would help Internet service users to make the best decision for themselves and choose the best Internet service that fits their needs. A qualitative method has been used to evaluate the efficiency and the utility of the proposed system prototype. The results showed the extent of participants' acceptance of the Internet Service Evaluation System.

• 한국IT서비스학회지
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• 제11권4호
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• pp.215-231
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• 2012

It is well known that SaaS(Software as a Service) changeover gives several advantages to organization. One of the advantages is the cost reduction effect of IT resources as well as IT human resources. Another one is the curtailment of software development workload in the field of informatization promotions. Nonetheless, it is hard to find comparison cases regarding the quantitative measurement of the introduction of SaaS before and after. Accordingly, when the Government IDC tries to adopt SaaS, it absolutely needs the empirical study whether SaaS is cost-effectiveness or not. In this study, we focus on variation in the Government administration common tasks, processes and labor costs. Using the Man-Month(MM) estimation methods, We verify that how much TCO(Total Cost of Ownership) is reduced per year.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권1호
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• pp.211-232
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• 2024

In this paper, we consider the resource allocation and offloading decisions of device-to-device (D2D) cooperative UAV-assisted mobile edge computing (MEC) system, where the device with task request is served by unmanned aerial vehicle (UAV) equipped with MEC server and D2D device with idle resources. On the one hand, to ensure the fairness of time-delay sensitive devices, when UAV computing resources are relatively sufficient, an optimization model is established to minimize the maximum delay of device computing tasks. The original non-convex objective problem is decomposed into two subproblems, and the suboptimal solution of the optimization problem is obtained by alternate iteration of two subproblems. On the other hand, when the device only needs to complete the task within a tolerable delay, we consider the offloading priorities of task to minimize UAV computing resources. Then we build the model of joint offloading decision and power allocation optimization. Through theoretical analysis based on KKT conditions, we elicit the relationship between the amount of computing task data and the optimal resource allocation. The simulation results show that the D2D cooperation scheme proposed in this paper is effective in reducing the completion delay of computing tasks and saving UAV computing resources.

• 한국통신학회논문지
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• 제36권9B호
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• pp.1066-1072
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• 2011

가상화를 통해 원하는 만큼의 컴퓨팅 파워와 데이터 저장 공간을 제공하면서도 관련된 IT자원의 유지보수 비용과 관리에서는 사용자를 해방시켜주는 많은 장점에도 불구하고, 클라우드 컴퓨팅이 가까운 미래에 실질적인 서비스로 자리잡고 활성화를 위해서는 먼저 넘어야 할 장벽들이 있다. 즉, 사용자의 제어 너머에 있는 클라우드 컴퓨팅 환경이 IT서비스와 인프라에 대해 사용자에게는 이용권만을 주기 때문에 비롯되는 여러 문제들이 생기게 된다. 가장 큰 이슈 중의 하나는 클라우드에 저장되는 정보의 보호 및 신뢰성 확보이다. 본 논문에서는 provenance 통한 클라우드 상의 데이터 신뢰확보에 대한 효과적이고 유용한 해법을 제안한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권2호
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• pp.826-845
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• 2017

Outsourcing computation is one of the most important applications in cloud computing, and it has a huge ability to satisfy the demand of data centers. Modular exponentiation computation, broadly used in the cryptographic protocols, has been recognized as one of the most time-consuming calculation operations in cryptosystems. Previously, modular exponentiations can be securely outsourced by using two untrusted cloud servers. In this paper, we present two practical and secure outsourcing modular exponentiations schemes that support only one untrusted cloud server. Explicitly, we make the base and the index blind by putting them into a matrix before send to the cloud server. Our schemes provide better performance in higher efficiency and flexible checkability which support single cloud server. Additionally, there exists another advantage of our schemes that the schemes are proved to be secure and effective without any cryptographic assumptions.

• 한국멀티미디어학회논문지
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• 제10권12호
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• pp.1663-1670
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• 2007

One-way hash chains are important cryptographic primitives and have been used as building blocks of various cryptographic applications. Advantages of one-way hash chains are their simplicity and efficiency for generation based on low-powered processors with short time. However, a drawback of one-way hash chains is their difficulty of control to compute interval values of one-way hash chains. That is, when hash values in one-way hash chain are used as encryption keys, if one hash value is compromised, then the attacker can compute other encryption keys from the compromised hash value. Therefore, direct use of one-way hash chains as encryption keys is limited to many cryptographic applications, such as pay per view system and DRM system. In this paper, we propose a new concept which is called interval hash chain using a hash function. In particular, proposed hash chains are made for only computing interval hash values by using two different one-way hash chains. The proposed scheme can be applied to contents encryption scheme for grading and partially usable contents in DRM system.