• Journal of Information Processing Systems
• /
• 제16권2호
• /
• pp.460-477
• /
• 2020

As one of the most significant challenges in the virtual data center, the virtual data center embedding has attracted extensive attention from researchers. The existing research works mainly focus on how to design algorithms to increase operating revenue. However, they ignore the energy consumption issue of the physical data center in virtual data center embedding. In this paper, we focus on studying the energy-aware virtual data center embedding problem. Specifically, we first propose an energy consumption model. It includes the energy consumption models of the virtual machine node and the virtual switch node, aiming to quantitatively measure the energy consumption in virtual data center embedding. Based on such a model, we propose two algorithms regarding virtual data center embedding: one is heuristic, and the other is based on particle swarm optimization. The second algorithm provides a better solution to virtual data center embedding by leveraging the evolution process of particle swarm optimization. Finally, experiment results show that our proposed algorithms can effectively save energy while guaranteeing the embedding success rate.

• 전기학회논문지
• /
• 제57권4호
• /
• pp.686-691
• /
• 2008

This paper proposes the concept of "virtual sensor data" and its application for real time obstacle avoidance. The virtual sensor data is virtual distance which takes care of the movement of the obstacle as well as that of the robot. In practical application, the virtual sensor data is calculated from the odometry data and the range sensor data. The virtual sensor data can be used in all the methods which use distance data for collision avoidance. Since the virtual sensor data considers the movement of the robot and the obstacle, the methods utilizing the virtual sensor data results in more smooth and safer collision-free motion.

• 디지털융복합연구
• /
• 제4권1호
• /
• pp.17-30
• /
• 2006

Recently, Modeling and Simulation, which have been received attention in various in dustries such as national defence, eduction and entertainment, have been researched, and related applications have been developed actively. Especially, it is focused on the to chnology of a virtual reality and a virtual simulation which represents the implementation technology for the simulation education related to the e-Learning industry. However, a solution is needed to fulfill the lack of technology and research about standardize d data elements which could be applied to virtual simulation technologies in common. Therefore, this article suggests the virtual simulation data elements to increase the educational effect of a virtual simulation and interoperability of data among LMS through reference to korean and international standards and the result of related area analysis. In other words, this article aims to define the expression of data element and to propose the guideline elements in the virtual simulation scope.

• Spatial Information Research
• /
• 제18권5호
• /
• pp.1-11
• /
• 2010

서울특별시는 2009년 초 4개의 GNSS 고정 기준국을 설치하고 네트워크 RTK 시스템을 구축하여 현재 운영 중에 있다. 현재는 무선인터넷을 이용한 VRS 측위 서비스와 후처리를 위한 고정 기준국 RINEX 데이터를 제공하고 있다. 본 연구에서는 서울특별시 네트워크 RTK 시스템의 활용성 증대 방안을 검토하고, Virtual RINEX 실용성 검토를 위한 실험을 수행하였다. 네트워크 RTK 시스템의 활용 다양화를 위한 검토는 1) GNSS 고정 기준국의 관측 데이터를 NTRIP을 통하여 타기관의 사용자 시스템으로 실시간 전송하고 수신측 기관에서는 이를 RINEX 데이터로 변환 생성하는 방법, 2) GNSS를 이용하여 주요 장대 시설물의 변위를 모니터링 하는 방법을 검토하였다. 또한 3) NTRIP을 이용한 GNSS Internet Radio로 VRS 보정 데이터를 네트워크 RTK 시스템으로부터 수신하고 무선모뎀을 이용, 소규모 작업 지역을 대상으로 방송하여 RTK측위를 실시하는 방법을 소개 하였다. Virtual RINEX 실용성검토를 위한 실험은 1) GNSS고정 기준국에서 관측한 기준국 데이터와 특정 지점에서 실제로 관측한 GNSS 관측 데이터로 후처리한 성과와 그 지점의 Virtual RINEX 데이터를 이동국 데이터로 한 후처리 성과를 비교하였다. 또한 2) 특정 지점에 대한 VRS RTK 측위 결과와 이동국 측위 지점에 대한 Virtual RINEX 데이터의 후처리 성과를 비교하였다. 그 결과, Virtual RINEX와 GPS 관측 성과는 거의 동일하여 향후 Virtual RINEX도 후처리 데이터로 사용할 수 있는 가능성을 확인하였고, VRS RTK 측위 성과는 Virtual RINEX 후처리 성과와 수 mm 이내 차이를 보여 산출된 성과가 거의 같음을 확인할 수 있었다.

• 한국의류학회지
• /
• 제45권6호
• /
• pp.965-977
• /
• 2021

The study aimed to analyze the functional differences in 3D virtual garment programs and compare body scan data with the corresponding 3D virtual models. We selected 3D virtual garment programs, formed virtual models in a representative size for high-school male cyclists, and analyzed them using the Design-X program. The results were as follows. In the 3D virtual garment programs, the anthropometric items for virtual model forming differed significantly from the standard anthropometric items suggested by Size Korea. Comparing the lower body scan data and virtual models formed by the 3D virtual garment programs, the biggest difference was in the shapes of the waist and hips, i.e., the flatness values of the waist and hips were different for each program in the cross-section view. In the lower body, a data-input-based program was needed for changing the exact measurement position of the waist circumference and hips' shape in detail. If a 3D virtual garment program provides functions for the virtual model's joint angle input and free motion transformation, it is expected to be widely used in the sportswear industry.

• 한국CDE학회논문집
• /
• 제15권5호
• /
• pp.343-353
• /
• 2010

Time to market and cost-efficient production are some of the challenge that manufacturing industries face. Modern methods of engineering can't help such organizations attain competitive advantage. To help these situations, MEMPHIS (Middleware for Exchanging Machinery and Product Data in Highly Immersive Systems) was introduced as an approach that enables VE (Virtual Engineering) and links engineering applications with VR (Virtual Reality) solutions. Thus an environment is provided to implement virtual design reviews and enable the application of virtual prototyping methods. However MEMPHIS could just handle Product data for virtual design review and simulation. In this paper, we newly define and develop the extended MEMPHIS that enables virtual manufacturing with Process, Resource and Plant data as well as Product data.

• 한국세라믹학회지
• /
• 제56권6호
• /
• pp.596-600
• /
• 2019

Artificial intelligence with a sufficient amount of realistic big data in certain applications has been demonstrated to play an important role in designing new materials or in manufacturing high-quality products. To reduce cracks in ceramic products using machine learning, it is desirable to utilize big data in recently developed data-driven optimization schemes. However, there is insufficient big data for ceramic processes. Therefore, we developed a numerical algorithm to make "virtual" manufacturing data sets using indirect methods such as computer simulations and image processing. In this study, a numerical algorithm based on the random walk was demonstrated to generate images of cracks by adjusting the conditions of the random walk process such as the number of steps, changes in direction, and the number of cracks.

• 한국정밀공학회지
• /
• 제17권7호
• /
• pp.63-73
• /
• 2000

Internet becomes very common tool for communication and data sharing. Virtual reality(VR) on web browser, and virtual prototyping and virtual manufacturing is widely used in many engineering folds. The reduction of overall development process and error minimization during data conversion becomes very crucial where sharing data via Internet and VR. This paper deals with the advantage and disadvantage of VRML format used in RP(Rapid Prototyping), and a software for RP data preparation is developed. If VRML format as an international standard for VR, is replaced with STL format, the weak points of STL format can be overcome and the technique related to virtual prototyping and virtual manufacturing can be addressed more systematically by sharing the data. The system developed in this work shows a good window to get access to a more realistic observation of an object fur an RP system from a long remote sites in a more systematic way.

• International Journal of Computer Science & Network Security
• /
• 제22권4호
• /
• pp.147-158
• /
• 2022

Cloud Computing offers flexible, on demand, ubiquitous resources for cloud users. Cloud users are provided computing resources in a virtualized environment. In order to meet the growing demands for computing resources, data centres contain a large number of physical machines accommodating multiple virtual machines. However, cloud data centres cannot utilize their computing resources to their total capacity. Several policies have been proposed for improving energy proficiency and computing resource utilization in cloud data centres. Virtual machine placement is an effective method involving efficient mapping of virtual machines to physical machines. However, the availability of many physical machines accommodating multiple virtual machines in a data centre has made the virtual machine placement problem a non deterministic polynomial time hard (NP hard) problem. Metaheuristic algorithms have been widely used to solve the NP hard problems of multiple and conflicting objectives, such as the virtual machine placement problem. In this context, we presented essential concepts regarding virtual machine placement and objective functions for optimizing different parameters. This paper provides a taxonomy of metaheuristic algorithms for the virtual machine placement method. It is followed by a review of prominent research of virtual machine placement methods using meta heuristic algorithms and comparing them. Finally, this paper provides a conclusion and future research directions in virtual machine placement of cloud computing.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제8권3호
• /
• pp.819-837
• /
• 2014

Data centers, which implement cloud service, have been faced up with quick growth of energy consumption and low efficiency of energy. 60GHz wireless communication technology, as a new option to data centers, can provide feasible approach to alleviate the problems. Aiming at energy optimization in 60GHz wireless data centers (WDCs), we investigate virtualization technology to assign virtual resources to minimum number of servers, and turn off other servers or adjust them to the state of low power. By comprehensive analysis of wireless data centers, we model virtual network and physical network in WDCs firstly, and propose Virtual Resource Mapping Packing Algorithm (VRMPA) to solve energy management problems. According to VRMPA, we adopt packing algorithm and sort physical resource only once, which improves efficiency of virtual resource allocation. Simulation results show that, under the condition of guaranteeing network load, VPMPA algorithm can achieve better virtual request acceptance rate and higher utilization rate of energy consumption.