• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.8
• /
• pp.3753-3771
• /
• 2016

Increasingly, numerous and various Internet-capable devices are connected in end user networks, such as a home network. Most devices use the combination of TCP and 802.11 DCF as a system platform, but whereas some devices such as a streaming video persistently generate traffic, others such as a motion sensor do so only intermittently with lots of pauses. This study addresses the issue of performance in this heterogeneous traffic wireless LAN environment from the perspective of fairness. First, instantaneous fairness is introduced as a notion to indicate how immediately and how closely a user obtains its fair share, and a new time-based metric is defined as an index. Second, extensive simulation experiments have been made with TCP Reno, Vegas, and Westwood to determine how each TCP congestion control corresponds to the instantaneous fairness. Overall, TCP Vegas yields the best instantaneous fairness because it keeps the queue length shorter than the other TCPs. In the simulations, about 60% of a fair share of the effective user bandwidth is immediately usable in any circumstance. Finally, we introduce two simple strategies for adjusting TCP congestion controls to enhance instantaneous fairness and validate them through simulation experiments.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.13 no.11
• /
• pp.5446-5463
• /
• 2019

Parallel computing system components should be harmonized, and this harmonization is kept existent using synchronization time. Synchronization time affects the system in two ways. First, if we have too little synchronization time, some tasks face the problem of harmonization, as they need appropriate time to update and synchronize with the system. Second, if we allocate a large amount of time, stall system created. Random allocation of synchronization time for parallel systems slows down not only the booting time of the system but also the execution time of each application involved in the system. This paper presents a simulator used to test and allocate appropriate synchronization time for distributed and parallel heterogeneous systems. The simulator creates the parallel and heterogeneous system to be evaluated, and lets the user vary the synchronization time to optimize the booting time. NS3-cGEM5 simulator in this paper is formed by HLA-RTI federation integration of the two independent architecture and network simulators - NS3 and cGEM5. Therefore, nodes created on these simulators need synchronizations for harmonized system performance. We tested and allocated the appropriate synchronization time for our sample parallel system composed of one x86 server and three ARM clients.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2002.11a
• /
• pp.405-408
• /
• 2002

Cluster is the cost-effective parallel processing environment, and consists of the off-the-shelf computers connected by the computer networks. The characteristics of cluster are the node heterogeneity, the variety of node load, and the variety of network load. Because these characteristics influence the performance of parallel program executions, the load sharing for cluster is important, and by using the proper load sharing strategy, we can reduce the execution time of parallel programs. In this paper, we propose modified GSS algorithm, aGSS. In the proposed load sharing algorithms aGSS, the size of tasks are decided using the BogoMTPS of node. From the result of out experiments, we conclude that the proposed aGSS algorithm is effective in the heterogeneous cluster.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.5
• /
• pp.812-814
• /
• 2015

In this letter, a distributed self-organized cell association scheme is proposed for heterogeneous cellular networks. In which each small cell uses a common self-organization strategy and takes its environment into account to establish its own cell association scheme. It is confirmed that the proposed cell association improves the user throughput and areal spectral efficiency compared to joint association.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.5
• /
• pp.1912-1931
• /
• 2018

In future wireless network, user experience and energy efficiency will play more and more important roles in the communication systems compared to their roles at present. Quality of experience (QoE) and Energy Efficiency (EE) become the widely used metrics. In this paper, we study a combinatorial problem of QoE and EE and investigate a fair power allocation in heterogeneous networks. We first design a new metric, QoE-aware EE (QEE) to reflect the relationship of QoE and energy. Then, the concept of Utopia QEE is introduced, which is defined as the achievable maximum QEE in ideal conditions, for each user. Finally, we transform the power allocation process to an optimization of ratio of QEE and Utopia QEE and use invasive weed optimization (IWO) algorithm to solve the optimization problem. Numerical simulation results indicate that the proposed algorithm can get converged and efficiently improve the system energy efficiency and the QoE for each user.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2014.10a
• /
• pp.354-356
• /
• 2014

Recently, The sensor technology Has been used in many fields, it is detected data of various types of sensors, is very difficult to integrate due to differences in the standards and each other unit. Also, when we providing a service or program on a data cloud, it is important that integrates of such data in order to take advantage of the detected data in the similar field. In this paper, we propose a approaches to integrating data to be provided as a service in the cloud of data arising from a heterogeneous sensors. The approaches are generating a standard meta-data based on ontology, it is mapping with detected data by the sensor data. Accordingly, the detected data is possible to improve the efficiency of data transfer between the sensor and the application by sending an application in a standard format.

• Journal of Information Processing Systems
• /
• v.19 no.5
• /
• pp.673-687
• /
• 2023

Convolutional neural network-based deep learning technology is the most commonly used in image identification, but it requires large-scale data for training. Therefore, application in specific fields in which data acquisition is limited, such as in the military, may be challenging. In particular, the identification of ground weapon systems is a very important mission, and high identification accuracy is required. Accordingly, various studies have been conducted to achieve high performance using small-scale data. Among them, the ensemble method, which achieves excellent performance through the prediction average of the pre-trained models, is the most representative method; however, it requires considerable time and effort to find the optimal combination of ensemble models. In addition, there is a performance limitation in the prediction results obtained by using an ensemble method. Furthermore, it is difficult to obtain the ensemble effect using models with imbalanced classification accuracies. In this paper, we propose a transfer learning-based feature fusion technique for heterogeneous models that extracts and fuses features of pre-trained heterogeneous models and finally, fine-tunes hyperparameters of the fully connected layer to improve the classification accuracy. The experimental results of this study indicate that it is possible to overcome the limitations of the existing ensemble methods by improving the classification accuracy through feature fusion between heterogeneous models based on transfer learning.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2010.05a
• /
• pp.430-433
• /
• 2010

In-vehicle networks have been developed to increase capacity and reduce wiring in the car. These would make communication possible with each heterogeneous networks by the advent of networks attached to the vehicle. However, these come with a variety of unique features in each network-specific communication which creates difficulty using and supporting the service. To solve this problem, local networks need a standard integration framework. In this paper, a framework, consists of a standard protocol using XML to improve compatibility and portability, is proposed and implemented. Each network is compatible with the framework by applying unique information and messages of the network in the XML standard ducument. The results obtained by implementation show that the framework supports the communication of information between heterogeneous in-vehicle networks.

• The Journal of Society for e-Business Studies
• /
• v.3 no.1
• /
• pp.23-41
• /
• 1998

In a centralized database system, all system components reside at a single platform. In recent years there has been a rapid trend toward the integration of information systems over multiple sites that are interconnected via a communication network, and users' needs are changed to integration of multiple information sites. Multi database System is one of solutions for integrating distributed heterogeneous databases. However the problems in multi database system are restriction in distributed environment support, limitation in integrating heterogeneous media type data, static integration, and data-only of integration. In order to solve these problems, we propose a hybrid database integration model, HyDIM. HyDIM is used for the integrating legacy multimedia data, adopting CORBA, MDS, and mediator. We demonstrate a prototype system far PDM application domain.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2014.10a
• /
• pp.643-644
• /
• 2014

정보기술의 발달과 인터넷의 확산 등의 사회적인 변화에 따라 고객을 효과적으로 만족시킬 수 있도록 기업은 고객과의 장기적인 관계를 구축하는 고객관계관리(CRM: Customer Relationship Management)을 사용하고 있다. 최근에는 블로그나 SNS등에 기업이 상품이나 서비스를 팔고자 하는 소비자들이 가득 모여 있기 때문에 실시간으로 소비자의 니즈를 파악할 수 있는 방법으로 트위터, 블로그, 카페 등 SNS 상의 빅 데이터를 분석하는 시스템을 이용한다. 본 논문에서는 고객의 보다 효율적인 피드백 수집분석을 위해 기존의 기업/기관에서 운영 및 관리하는 내부 CRM 데이터와 SNS 상의 외부 데이터를 연동하여 분석할 수 있는 이기종 데이터의 통합 분석엔진 시스템을 제안한다. 이를 의료서비스에 적용하여 내부 데이터인 매출, 방문자 수, 진료과 정보, 환자 정보, 고객 불만 유형 등을 분석하고 소셜데이터를 통해 해당 의료기관에 대한 소비자 경험 (진료, 시설 등) 정보를 수집한다.