• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제16권4호
• /
• pp.1187-1208
• /
• 2022

One of the main goals of wireless sensor networks (WSNs) is to utilize the energy of sensor nodes effectively and maximize the network lifetime. Thus, this paper proposed a routing protocol for WSNs based on virtual force disturbing mobile Sink node (VFMSR). According to the number of sensor nodes in the cluster, the average energy and the centroid factor of the cluster, a new cluster head (CH) election fitness function was designed. At the same time, a hexagonal fixed-point moving trajectory model with the best radius was constructed, and the virtual force was introduced to interfere with it, so as to avoid the frequent propagation of sink node position information, and reduce the energy consumption of CH. Combined with the improved ant colony algorithm (ACA), the shortest transmission path to Sink node was constructed to reduce the energy consumption of long-distance data transmission of CHs. The simulation results showed that, compared with LEACH, EIP-LEACH, ANT-LEACH and MECA protocols, VFMSR protocol was superior to the existing routing protocols in terms of network energy consumption and network lifetime, and compared with LEACH protocol, the network lifetime was increased by more than three times.

• Korean Journal of Computational Design and Engineering
• /
• 제15권3호
• /
• pp.167-177
• /
• 2010

In recent years, the use of high-resolution tiled display system which does not have restrictions on the size of the screen and implements various layout of tile is increasing in order to evaluate the digital mock-up in physical scale or explore large engineering data set in detail. In this study, we developed multi-channel distributed visualization system which provides a virtual reality-based visual contents using 3D open-source graphics engine. Efficient data structures and exchange methods were proposed as a scene synchronization technology in PC cluster environments. DLP-Cube based tiled visualization system which provides $5{\times}2$ layout of display wall was developed and we validated our approach using this system. In addition, we introduced integrated control program that administrates PC cluster environment in remote and controls the layout of display channels.

• Journal of the Korea Computer Industry Society
• /
• 제2권9호
• /
• pp.1239-1244
• /
• 2001

The Virtual Interface Architecture (VIA) is usually suggested as a new standard high-performance communication of the cluster systems. However the VIA specification aims for platform independence, the current Intel VI Provider Library (VIPL) design favors systems with Intel architecture processors running the Windows operating system (OS). This paper aims for clarifying the guesstion problem of VIA and VIPL in the newtrul time of CPU Architecture and OS further more, It suggests the solution aiming the communication in the other CPU or OS

• KIISE Transactions on Computing Practices
• /
• 제21권1호
• /
• pp.13-18
• /
• 2015

Computational science simulations have been used to enable discovery in a broad spectrum of application areas, these simulations show irregular demanding characteristics of computing resources from time to time. The adoption of virtualized high performance cloud, rather than CPU-centric computing platform (such as supercomputers), is gaining interest of interests mainly due to its ease-of-use, multi-tenancy and flexibility. Basically, provisioning a virtual cluster, which consists of a lot of virtual machines, in a real-time has a critical impact on the successful deployment of the virtualized HPC clouds for computational science simulations. However, the cost of concurrently creating many virtual machines in constructing a virtual cluster can be as much as two orders of magnitude worse than expected. One of the main factors in this bottleneck is the time spent to create the virtual images for the virtual machines. In this paper, we propose a novel technique to minimize the creation time of virtual machine images and improve I/O performance of the provisioned virtual clusters. We also confirm that our proposed technique outperforms the conventional ones using various sets of experiments.

• 한국방재학회:학술대회논문집
• /
• 한국방재학회 2010년도 정기 학술발표대회
• /
• pp.51.2-51.2
• /
• 2010

A novel approach of Poisson cluster stochastic rainfall generator was validated in its ability to reproduce important rainfall and watershed response characteristics at 104 locations of the United States. The suggested novel approach - The Hybrid Model(THM), as compared to the traditional ones, has an additional function to account for the year-to-year variability of rainfall statistics. The two-sample Kolmogorov-Smirnov test was used to see how well THM and traditional approach of Poisson cluster rainfall model reproduce the distribution of the following hydrologic variables: monthly maximum rainfall depths with 1, 3, 6, 12, and 24 hour duration, monthly maximum flow peaks at the virtual watersheds with Curve Number of 50, 60, 70, 80 and 90; and monthly runoff depths at the same virtual watersheds. In all of the testing variables, THM significantly outperformed the traditional approach. This result indicates that the year-to-year variability of rainfall statistics contains important information about the characteristics of rainfall processes that were not considered by the conventional approach of Poisson cluster rainfall modeling and that further considering it in rainfall simulation will enhance the performance of the rainfall models.

• Journal of KIISE:Computer Systems and Theory
• /
• 제29권10호
• /
• pp.539-549
• /
• 2002

PC cluster-based Information Retrieval (IR) systems improve their performances by parallel processing of query terms using cluster nodes. However TCP/IP based communication used to exchange data between cluster nodes prevents the performance from being improved further. The user-level communication mechanisms solve the problem by eliminating the time-consuming kernel access in exchanging data between cluster nodes. The Virtual Interface Architecture (VIA) is one of the representative user-level communication mechanisms which provide low latency and high bandwidth. In this paper, we propose a VIA-based parallel IR system on a PC cluster. The IR system is implemented using the following three communication methods: Sealable Coherent Interface (SCI) based VIA, MPI on SCI based VIA, MPI on Fast Ethernet based VIA. Through experiments, the performances of the three methods are analyzed in various aspects.

• Journal of the Korea Society of Computer and Information
• /
• 제19권11호
• /
• pp.1-7
• /
• 2014

In this paper, we propose a virtual machine(VM) remapping scheme that reduces VM relocation time on a cloud cluster. The proposed scheme finds VMs that should be migrated in sequence from a given VM map, and exchanges destinations of some VMs among them to reduce the VM relocation time. The VMs, the destinations of which will be exchanged, are chosen based on the amount of physical machine's available resources and migration completion time. The exchange of destinations is repeated until the VM relocation time cannot be shortened any further. Through a simulation, we show that the proposed scheme reduces VM relocation time by 42.7% in maximum.

• Asian Journal of Innovation and Policy
• /
• 제9권2호
• /
• pp.164-186
• /
• 2020

It is generally known that a Science and Technology Park - as a representative example of an Innovation Cluster - produces network synergy among industry, university, research institutes, and other innovation actors in a specific area, so that it has a competitive edge over other regions in technological innovation. However, as the novel Coronavirus (COVID-19) pandemic unfolds, it has become necessary to reduce face-to-face contacts and this could lead to lesser network synergy being produced in an Innovation Cluster. With this background, this research was designed and conducted to evaluate how COVID-19 has changed the activities in Innovation Clusters and explore future development scenarios. In order to find out the changes occurring in an Innovation Cluster, a survey was conducted among the people in Science and Technology Parks. The survey result shows that people are experiencing difficulties in technological innovation and support activities, and face-to-face contacts have been reduced in the Innovation Cluster. A scenario planning sought to explore the future development of the Innovation Cluster. It suggests that the transformation into a Digital Innovation Cluster, which is less affected by physical distance, but can still maintain the effectiveness of the networks, can be the key strategy for the future Innovation Cluster.

• Journal of KIISE:Computing Practices and Letters
• /
• 제9권6호
• /
• pp.635-645
• /
• 2003

One of very important features that are necessarily supported by clustered parallel computer systems is a single I/O system image in which users can access both the local and remote I/O resources transparently. In this paper, we propose an efficient disk sharing technique supporting a single disk I/O system image architecture. The design separates the I/O subsystem of a cluster into the file system and a set of virtual hard disk drivers. The virtual hard disk driver deals with a hard disk in the remote node as a local hard disk. All services provided by it are performed in the device driver level without any modification of file systems. Users can, therefore, access all the disks in the cluster regardless of their locations. Our virtual hard disk driver is implemented under the linux, and also tested in a linux cluster system. We find by experiments that it can successfully support a single disk I/O space, and at the same time it shows better performance than NFS. We are sure that this paper can be a guideline for single I/O space of other devices to be easily constructed.

• Journal of Digital Contents Society
• /
• 제10권2호
• /
• pp.249-258
• /
• 2009

As wireless internet markets become larger than before, many mobile applications are also being developed actively. In this circumstances mobile devices such as cell phones, PDAs are playing an important role to satisfy the user's need of ubiquitous computing. Due to the hardware limitations, however, the mobile devices like PDA can not run large-scale softwares by itself. The main goal of this paper is to make large-scale applications runnable on PDA. To accomplish this, we used the PDA-JPVM cluster computing engine which has been already developed by us. We found out by running the applications and the performance evaluation that large-scale Java softwares can easily run on the hardware-limited PDA. And the performance evaluation results are also presented.