• Journal of KIISE:Computer Systems and Theory
• /
• v.37 no.3
• /
• pp.147-160
• /
• 2010

The system virtualization shows interest in the consolidation of servers for the efficient utilization of system resources. There are many various researches to utilize a server machine more efficiently through the system virtualization technique, and improve performance of the virtualization software. These researches have studied with the activity to control the resource allocation of virtual machines dynamically focused on CPU, or to manage resources in the cross-machine using the migration. However, the researches of the memory management have been wholly lacking. In this respect, the use of memory is limited to allocate the memory statically to virtual machine in server consolidation. Unfortunately, the static allocation of the memory causes a great quantity of the idle memory and decreases the memory utilization. The underutilization of the memory makes other side effects such as the load of other system resources or the performance degradation of services in virtual machines. In this paper, we suggest the dynamic allocation of the memory in Xen to control the memory allocation of virtual machines for the utilization without the performance degradation. Using AR model for the prediction of the memory usage and ACO (Ant Colony Optimization) algorithm for optimizing the memory utilization, the system operates more virtual machines without the performance degradation of servers. Accordingly, we have obtained 1.4 times better utilization than the static allocation.

• International Journal of Automotive Technology
• /
• v.6 no.4
• /
• pp.333-340
• /
• 2005

In order to better quantify the contribution from nonroad sources to emission inventories, it is important to understand not only the emissions rates of these engines but also activity patterns that can be used to accurately portray their in-use operation. To date, however, very little information is available on the actual activity patterns of nonroad equipment. In this study, a total of 18 pieces of nonroad equipment were instrumented with collected data including intake manifold air pressure (MAP), exhaust temperature and, on a subset of vehicles, engine rpm and throttle position. The equipment included backhoes, compactors, dozers, motor graders, loaders and scrappers used in applications such as landfilling, street maintenance and general roadwork. The activity patterns varied considerably depending on the type of equipment and the application. Daily equipment operating time ranged from less than 30 minutes to more than 8 hours, with landfill equipment having the highest daily use. The number of engine starts per day ranged from 3-11 lover the fleet with an average of 5 starts per day. The average percent idle time for the fleet was approximately $25\%$ with a range from 11 to $65\%$ for individual pieces of equipment. Duty cycles based on exhaust temperature/throttle position profiles were also developed for two graders and one dozer.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.20 no.6
• /
• pp.67-77
• /
• 2017

Demands for housing has diversified recently due to low birth rate and the growth of aging population. Also, a share of idle houses and obsolete houses over 20 years old is gradually rising. Therefore, there is a need for a sustainable, environment-friendly improvement policy that is in line with a new housing paradigm and avoids full-scale new construction, such as a customized housing renovation plan considering local economic circumstances. Therefore, afforestation system applicable to buildings are assessed positively, but lack objective performance evaluation. Through one-year, long-term monitoring of replicated obsolete buildings that have poor insulation performance, this study calculated monthly average power consumption and analyzed power charges by applying pricing plans before and after the revision of progressive tax in order to examine economic effects expected by applying the afforestation system. In the obsolete buildings, the study showed that monthly average power consumption was reduced by 16.6kWh with 5.2% average reduction rate. Highest reduction was made in July at 11.3%. Aggregate monthly power consumption charges were relatively high in winter before and after the revision of progressive tax. Power charges reduction effect was highest in March when monthly power consumption was reduced to 300kWh level by applying the afforestation system.

• The Journal of Industrial Distribution & Business
• /
• v.8 no.6
• /
• pp.75-86
• /
• 2017

Purpose - The purpose of this study is to grasp the concept, characteristics and application status of sharing economy, and to derive a research model based on sharing economic service, and to analyze factors and influences of consumers' intention to reuse of sharing economy. Research design, data, and methodology - The questionnaires were created to examine variables for practical and theoretical implications. After pilot survey, conducted for 24 days from March 10th to April 2st in 2017, total numbers were 377. But 330 copies were used for the analysis with IBM SPSS Statistics 23.0 and IBM SPSS AMOS 23.0. The structural equation model was applied for this. Results - First, sharing economic services remain at an early stage, but it is meaningful to identify the revenue mechanism of the business model of the sharing economic platform. Second, in this study, it is meaningful that we systematized the theoretical structure by examining existing studies on the characteristics of the sharing economic service and consumer characteristics, and by examining empirically. Third, Satisfaction and Reliability are related to the characteristics of Sharing Economic Service (Security, Convenience, Discount, Sharing, Social Interaction), Consumer Characteristics (Personal Innovation, Word-of-Mouth) It is meaningful to broaden the understanding of the factors by verifying the mediating effect. Fourth, the sharing economy business is meaningful in that it is a new consumption trend that changes the meaning of consumption to consumers. Gradually, more and more people are recalling that purchasing something is not consumption, but sharing and borrowing is also consumption. In other words, through the sharing economy, consumers can experience more products and services, have more choices, and are expected to have a positive impact on economic growth by increasing the utilization of idle resources. Conclusions - Currently, the sharing economy is growing rapidly all over the world. Therefore, in the subsequent study, it is necessary to compare Korea and China's sharing economy and study the cultural and social characteristics of Korea and China. In particular, I think that steady research is necessary for more precise and specific direction on the influence of the shared economy.

• Journal of Information Processing Systems
• /
• v.6 no.3
• /
• pp.413-434
• /
• 2010

Wireless sensor networks are usually characterized by dense deployment of energy constrained nodes. Due to the usage of a large number of sensor nodes in uncontrolled hostile or harsh environments, node failure is a common event in these systems. Another common reason for node failure is the exhaustion of their energy resources and node inactivation. Such failures can have adverse effects on the quality of the real-time services in Wireless Sensor Networks (WSNs). To avoid such degradations, it is necessary that the failures be recovered in a proper manner to sustain network operation. In this paper we present a dynamic Energy efficient Real-Time Job Allocation (ERTJA) algorithm for handling node failures in a cluster of sensor nodes with the consideration of communication energy and time overheads besides the nodes' characteristics. ERTJA relies on the computation power of cluster members for handling a node failure. It also tries to minimize the energy consumption of the cluster by minimum activation of the sleeping nodes. The resulting system can then guarantee the Quality of Service (QoS) of the cluster application. Further, when the number of sleeping nodes is limited, the proposed algorithm uses the idle times of the active nodes to engage a graceful QoS degradation in the cluster. Simulation results show significant performance improvements of ERTJA in terms of the energy conservation and the probability of meeting deadlines compared with the other studied algorithms.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.12A
• /
• pp.1111-1119
• /
• 2005

A single fiber cut can potentially influence a total of 1.6 Tbps of traffic and is surprisingly frequent and results in significant loss of traffic. The survivability as we as the resource utilization of the connection in optical networks is important. Existing protection mechanisms to rapidly recover the failures allocate the backup path just SRLG-disjointed with working path. Those did not consider the unbalanced resource share of backup paths. The backup paths can be centralized on the specific link so that the idle resource is not used. As a result, as those do not efficiently use the resource the whole resource utilization is not so good. So we propose the mechanism to enhance the resources utilization as settling down the unbalanced resource share. Our purpose is to improve the link utilization as distributing the maximum link load.

• The Journal of Society for e-Business Studies
• /
• v.25 no.1
• /
• pp.1-12
• /
• 2020

Recently, research using machine learning have shown remarkable results in various domains, leading to the fact that leaning-based dispatchers have intrigued interest in both academia and industry. To improve the performance of the dispatcher, each dispatch decision needs to be evaluated in detail. However, existing studies on visualization techniques for manufacturing lines have mainly focused on illustrating the performance indicators or abnormal patterns. In this paper, we propose a monitoring system that displays a variety of information about the manufacturing line along with alternatives at the time of each dispatching decision being made. Furthermore, the proposed system effectively represents the cause of the idle time of resources and the change of the performance index over time.

• Journal of Internet Computing and Services
• /
• v.7 no.6
• /
• pp.87-103
• /
• 2006

Advances in computer and network technology provide new computing environment that were only possible with supercomputers before. In order to provide the environment, a distributed runtime system has to be provided, but most of the conventional distributed runtime systems lack in providing dynamic and flexible system reconfiguration depending on workload variance, due to a static architecture of fixed master node and slave working nodes. This paper proposes and implements a new model for distributed job allocation and management which is a distributed runtime system is P2P environment for flexible and dynamic system reconfiguration. The implemented systems enables job program transfer and management, remote compile and execution among cooperative developers based on P2P standard protocol Jxta platform. Since it makes dynamic and flexible system reconfiguration possible, the proposed method has some advantages in that it can collect and utilize idle computing resources immediately at a needed time for distributed job processing. Moreover, the implemented system's effectiveness and performance increase are shown by applying and processing the crawler jobs, in a distributed way, for collecting a large amount of data needed for internet search.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.1C
• /
• pp.54-62
• /
• 2012

A Wi-Fi mesh network providing multi-hop wireless connections based on IEEE 802.11 PHY/MAC technology has recently received a significant attention as a network infrastructure that interconnects RFID systems and wireless sensor networks (WSNs). However, the current IEEE 802.11 contention-based MAC protocol cannot fully utilize the network capacity due to eithor frame collisions or unused network resources. In this paper, we propose a novel multi-channel scheduling MAC (MCS-MAC) protocol for Wi-Fi mesh networks. Under the secondary interference model of Wi-Fi mesh networks, the MCS-MAC protocol can maximize the network throughput via activation of collision-free links that has a maximal link weight. Through the simulations, we show that the throughput of the MCS-MAC protocol is at least three times higher than that of existing MAC protocols in Wi-Fi mesh networks.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.39 no.1
• /
• pp.1-13
• /
• 2002

In Distributed Batch-processing Systems (DBSs), CPU-intensive jobs are automatically transferred and executed using idle computers across a network, there by increasing the resource usage and throughput. To be successful, the systems must guarantee the scalablility, fault-tolerance, and flexibility of dynamic configurations. In practice, however, it is very difficult to provide such capabilities in a non-deterministic environment in which the available set of resources is unpredictable because of network failures, computer failures, or voluntary withdrawal from a pool by a machine owner. In this paper, we present the design and implementation of the J-JDBS (Jini-based Java Distributed Batch-processing System) system which is based on the core Jini services like Discovery service, Lookup service, Lease service and etc. We show that the Jini core services can be very effectively used to build reliable, scalallle, fault-tolerant, and flexible DBS systems with little effort.