• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38C no.7
• /
• pp.587-594
• /
• 2013

With the development of web 2.0 and the rapid diffusion of smart devices, current web service, which only provides very limited information and service, has been transformed into user-friendly and comprehensive web service called mash-up service. Mash-up service is defined as comprehensive service that is created by combining variety of web services. When composing a mesh-up service, Open API is used as web service interface. Current mash-up service, however, has fundamental problem in that it could not satisfy the various needs of users who want I-centric personalized service because it is developed and provided by service developers. To overcome these obstacles, a lot of studies on mesh-up framework are being performed for improving mash-up proess though, it is still in beginning stage. In this paper, we introduce an API selection and compostion method as the key technology for mesh-up framework that support the automatic creation of mesh-up service.

• The Journal of the Korea Contents Association
• /
• v.12 no.6
• /
• pp.32-40
• /
• 2012

This study is a case analysis for user interface(UI) design of spectrophotometer which is widely used in the field of chemistry, biology and environment, based on user experience(UX). Generally, experimental equipment developments are centered on functionality and technology, and the interface for interaction between the user and the machine is developed only by the engineers who do not have much consideration for the users. From this background, this study tried to find out how UX could melt into UI so that a kind of spectrophotometers can be designed to help the work process of researchers in the real context by examining and analyzing the real users' experiences and also considering the developer's perspective. As a result, it was possible to improve UI and was found that redefinition of the goal of UI, time-efficiency, security, and sufficient information delivery are essential to the design of user interface for spectrophotometers.

• Journal of KIISE:Computer Systems and Theory
• /
• v.29 no.6
• /
• pp.346-353
• /
• 2002

The explosive increase of World Wide Web usage has incurred significant amount of network traffic and server load. To overcome these problems, web proxy caching replicates frequently requested documents in the web proxy closer to the users. Cache utilization depends on the replacement policy which tries to store frequently requested documents in near future. Temporal locality and Zipf frequency distribution, which are commonly observed in web proxy workloads, are considered as the important properties to predict the popularity of documents. In this paper, we propose a novel cache replacement policy, called Adaptive LFU (ALFU), which incorporates 1) Zipf frequency distribution by utilizing LFU and 2) temporal locality adaptively by measuring the amount of the popularity reduction of documents as time passed efficiently. We evaluate the performance of ALFU by comparing it to other policies via trace-driven simulation. Experimental results show that ALFU outperforms other policies.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.46 no.2
• /
• pp.1-10
• /
• 2009

Energy efficient operations are essential to increase the life time of wireless sensor network. A cluster-based protocol is the most common approach to preserve energy during a data aggregation. This paper deals with an energy awareness and autonomous clustering method based on time delay. This method consists of three stages. In the first phase, Candidate Cluster Headers(CCHs) are selected based on a time delay which reflects the remaining energy of a node, with considering coverage efficiency of a cluster. Then, time delay is again applied to declare Cluster Headers(CHs) out of the CCHs. In the last phase, the issue on an orphan node which is not included into a cluster is resolved. The simulation results show that the proposed method increases the life time of the network around triple times longer than LEACH(Low Energy Adaptive Cluster Hierarchy). Moreover, the cluster header frequency is less diverse, and the energy on cluster heads is less spent.

• Bulletin of the Society of Naval Architects of Korea
• /
• v.27 no.1
• /
• pp.3-10
• /
• 1990

Hull form can be described numerically by two approaches, one is to describe a hull form with a set of curves("curve approach"), and the other is to describe it with surfaces directly("surface approach"). This paper describes the numerical definition scheme of hull form using curve approach method which defines the hull form by a set of curves consisting of 2-dimensional transverse section curves and 3-dimensional longitudinal curves. A set of curves in the hull form definition scheme is described by the modified cubic spline which modified the general parametric cubic spline in order to ensure a very smooth curvature distribution within the curve segment even though a curve segment has large tangent angle at its end points. Illustrative examples are given showing the application of the method to represent the hull form of SWATH ship and oceanographic research vessel. Also, examples for hull form transformation are shown by using this method connected with transformation technique.

• Journal of the Korea Convergence Society
• /
• v.8 no.3
• /
• pp.185-190
• /
• 2017

This study investigates the bending stress, shear stress and deformation energy happening at the inner fiber structure when the bending moment is applied to he specimen with flat shape composed of carbon fiber. As CFRP is composed of innumerable fibers with multi-axes, the stress under bending condition can be effectively distributed. Theses stresses is shown to increase again at the starting point as this angle of $60^{\circ}$. Therefore, the condition at the stacking angle of $60^{\circ}$ is seen to become most adequate under the state where the bending stress happens. On the basis of this study result, the damage property by the bending at the plate due to stacking angle was examined through the analytic approach. it is thought that this study can be devoted to the safe design for damage prevention and durabilty improvement. Also, the esthetic sense can be shown as the designed factor of shape with flat plate is grafted onto the convergence technique.

• Journal of the Economic Geographical Society of Korea
• /
• v.16 no.4
• /
• pp.585-596
• /
• 2013

This study aims to identify the process by which local farmers are integrated into the transnational agri-food system. To that end, this study investigated the purpose and reality of the contract farming for Gold Kiwifruit between Zespri International, a transnational fruit producer based in New Zealand, and farmers in Seogwipo-si, Jeju Island. Through this contract farming, Jeju farmers were contributing to Zespri's global distribution strategy and helping the corporation meet local demand. In the process, local farmers were being integrated into the transnational agri-food system led by Zespri. In the cooperation between these two parties, the company took a limited role in providing production resources, and it consulted local producers in applying production technologies to local sites. Thanks to such practices, the company's influence on local farming was limited, and local farmers were able to function proactively in production. Therefore, the company and the farmers maintained a horizontal relationship.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.10a
• /
• pp.866-869
• /
• 2015

With the advance in semiconductor technology, the number of elements that can be integrated in system-on-chip(SoC) increases exponentially, and thus voltage scaling is indispensable to enhance energy efficiency. Near-threshold voltage computing(NTC) improves the energy efficiency by an order of degree, hence it is able to overcome the limitation of conventional super-threshold voltage computing(STC). Although NTC-based low performance manycore system can be used to maximize energy efficiency, it demands more number of cores to sustain the performance, which results in considerable increase of area. In this paper, we analyze NTC manycore architecture considering the trade-offs between performance, power, and area. Therefore, we propose an algorithmic methodology that can optimize power consumption and area while satisfying the required performance by determining the constrained number of cores and size of caches and clusters in NTC environment. Experimental results show that proposed NTC architecture can reduce power consumption by approximately 16.5 % while maintaining the performance of STC core under area constraint.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.22 no.6
• /
• pp.527-532
• /
• 2009

In this paper simulations for the impact into ceramics and/or metal materials have been discussed. To model discrete nature for fracture and damage of brittle materials, we implemented cohesive-law fracture model with a node separation algorithm for the tensile failure and Mohr-Coulomb model for the compressive loading. The drawback of this scheme is that it requires a heavy computational time. This is because new nodes are generated continuously whenever a new crack surface is created. In order to reduce the amount of calculation, parallelization with MPI library has been implemented. For the high-speed impact problems, the mesh configuration and contact calculation changes continuously as time step advances and it causes unbalance of computational load of each processor. Dynamic load balancing technique which re-allocates the loading dynamically is used to achieve good parallel performance. Some impact problems have been simulated and the parallel performance and accuracy of the solutions are discussed.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.17 no.6
• /
• pp.113-119
• /
• 2013

A main oxidizer shut-off valve (MOV) controls the supply of cryogenic liquid oxygen to the combustion chamber of liquid rocket engines by on/off operations. The main subjects to be introduced are not only the valve transient response during valve on/off procedures but also the characteristics of pneumatic and seat/poppet parts as core technologies in the development of the MOV, which is expected to be adopted for the Korea Space Launch Vehicle II. It is shown that the analytical prediction of the transient valve travel is in good agreement with experimental results. Friction and elastic forces on the valve moving part are quantitatively evaluated by structural analysis.