• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5669-5684
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• 2018

The new mobile edge network architecture has been required for an increasing amount of traffic, quality requirements, advanced driver assistance system for autonomous driving and new cloud computing demands on highway. This article proposes a hierarchical cloud computing architecture to enhance performance by using adaptive data load distribution for buses that play the role of edge computing server. A vehicular dynamic cloud is based on wireless architecture including Wireless Local Area Network and Long Term Evolution Advanced communication is used for data transmission between moving buses and cars. The main advantages of the proposed architecture include both a reduction of data loading for top layer cloud server and effective data distribution on traffic jam highway where moving vehicles require video on demand (VOD) services from server. Through the description of real environment based on NS-2 network simulation, we conducted experiments to validate the proposed new architecture. Moreover, we show the feasibility and effectiveness for the connected car media service on highway.

• International Journal of Contents
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• v.14 no.1
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• pp.7-11
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• 2018

Digital technology has been changing everyday life of ordinary people let alone the structure of world industry. The elderly care service is also going through changes influenced by the unavoidable impact from torrents of digital technologies. There are numerous reports and news about the digital technologies increasing the efficiency and effectiveness of care service yet lacking systematic understanding of the sources of such improvement. This study aims to present a new classification framework for digital elderly care service innovation to fully utilize the power of digital technologies drawing on insights from innovation studies and service studies. First, 4 features of digital technologies are identified as sources of new value in service innovation. The co-creation of value by users and producers in service and technology development is discussed to illuminate users' contributions to service innovation. Communication of needs and ideas with producers and application of new technologies into everyday practice of life are identified as the source of new value which can be attributed to the elderly. Customization along with efficiency gains is the key to digital elderly care service innovation. The classification framework, thus, incorporates the needs of the elderly as one axis of criteria in the conventional technology-centered framework. The new classification framework would help give due weight to user-driven or demand-driven innovation in the elderly care service R&D activities.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.8
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• pp.3904-3917
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• 2017

IP multimedia subsystem (IMS) is an open standardized architecture for delivering multimedia service over IP network in a route-agnostic manner. With the increasing popularity of conversational class service, the delivery of a traffic flow with a certain bandwidth demand over a single network path is either not possible or not cost-effective. Multipath transmission is considered to be a promising solution to provide high-quality delivery service. This paper proposes a software defined service overlay network (SDSON) based multipath transmission framework for IMS, which is complementary to existing network architecture. The framework transforms original two-party session negotiation into three-party session negotiation that supports participants to negotiate multipath transmission capacity and path information by signaling message. Based on existing IETF standards, SIP and SDP are scalable to support these functions. Finally, the proposed framework is fully implemented on open source platform and examined by experiments. Experimental results show that multipath-enabled IMS is an effective way to improve the delivery performance of conversational class service.

• IEMEK Journal of Embedded Systems and Applications
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• v.6 no.4
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• pp.249-254
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• 2011

A user desktop service can be made available on internet or local area network with the help of virtualization and cloud technologies. The service is usually called a virtual desktop or a desktop cloud. However, a user interface is limited to I/O capabilities of a user's mobile terminal. In order to enhance a user interface on a remote virtual desktop, it is important to connect full-featured I/O devices which are founded locally. Our previous work called SoD (System-on- Demand) has proposed a technique to associate local full-featured I/O devices with a remote virtual desktop in Xen. On the technique, it is required to install a SoD client agent in a user's mobile terminal for connecting a remote virtual desktop. In this paper, we propose a new framework called Web-SoD that does not require any explicit installation to make SoD service available. The SoD client agent is provided by the web technology so that the agent can be installed transparently, and the platform independency is also achieved. Due to insufficient network socket performance of current web technologies, we extend Native Client (NaCl) proposed by Google to support a network functionality by modifying a NaCl library and a service runtime. With conducted experiment, we show that the network extension supports a full socket functionality over the compromised overhead on the web environment.

• 한국경영정보학회:학술대회논문집
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• 2007.11a
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• pp.367-373
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• 2007

최근 소프트웨어 유통방식은 웹(Web) 2.0 시대의 도래와 더불어 SOA(Service Oriented Architecture) 웹 서비스(Web Service), 온 디멘드(On Demand), 컴퍼넌트(Component) 등의 개념 및 기술의 발전으로 ASP(Application Service Provider) 방식에서 SaaS(Soft as a Service) 방식으로 빠르게 진화하고 있다. 새롭게 등장하고 있는 SaaS 비즈니스 모델의 시장 경쟁력 결정 요인 분석은 SaaS 비즈니스 모델 중에서도 국내 가장 대표적인 그룹웨어, CRM, ERP 를 중심으로 전략경영이론을 도입하여 기업의 내부 및 외부 경쟁력 결정요인을 마이클포터, 동인분석, 주요 성공요인 분석, SWOT 를 중심으로 접근하고자 한다. 설문조사를 통한 주요 SaaS 비즈니스 모델별 시장 경쟁력 결정 요인에 대한 시론적인 분석 결과는 SaaS 시장 진출 신규 기업 및 정부의 SaaS 시장 육성 방향 설정 그리고 후속적인 연구의 방향을 결정하는데 중요한 벤치마킹 자료로 활용될 수 있을 것으로 기대된다.

• Journal of Technology Innovation
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• v.13 no.1
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• pp.295-315
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• 2005

The mobile telecommunication service industry plays major role of the realization to the perfect information society in the 21st century and has a great influence in society and culture. The government has enticed the mobile company to keep up to make the mobile service fee low. In this situation, this paper estimates consumer surplus and price elasticity with on-line survey data from the consumer of mobile service. The total estimated consumer surplus of the market is reached to 6.43trillion won. The consumer surplus from SKT is estimated to 4.98trillion won and 1.66trillion won and 0.67trillion won was made by KTF and LGT respectively. The result also shows that consumer surplus is expected to be increased by the increase of the mobile service demand and the sales.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.1
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• pp.47-56
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• 2012

Service Parts Management is defined as a supply management associated with service parts from the part suppliers to the final customer. A series of process to improve the customer service level by forecasting the demand and to minimize cost by maintaining the inventory level is included. Uniqueness such as missing value correction, the data pattern analysis and planned order system is designed and implemented. Main feature of order management system is to calculate order amount and order time based on selection of optimal forecasting algorithm.

• Journal of Korea Society of Industrial Information Systems
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• v.18 no.6
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• pp.1-8
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• 2013

Recently, as increasing use of smartphone, the development of social network service(SNS) applications is very active because of the mobility of smartphone. In addition, as the demand of the location based service(LBS) supporting mobile information is expanded, LBS combined with SNS improves the usability of smart phones. This paper proposes the smartphone application that provides the information for SNS generated depending on the location, by tracking the user's location in real time.

• Journal of information and communication convergence engineering
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• v.18 no.2
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• pp.100-105
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• 2020

With the advent of the 5G era, the rapid growth in demand for mobile content services has increased the need for additional backhaul investment. To meet this demand, employing a content delivery network (CDN) and optical access solution near the last mile has become essential for the configuration of 5G networks. In this paper, a cache-enabled architecture using the passive optical network (PON) is presented to serve video on demand (VoD) for users. For efficient use of mobile backhaul, I propose a request deduplication scheme (RDS) that can provide all the requested services missed in cache with minimum bandwidth by eliminating duplicate requests for movies within tolerable range of the quality of service (QoS). The performance of the proposed architecture is compared with and without RDS in terms of the number of requests arriving at the origin server (OS), hit ratio, and improvement ratio according to user requests and cache sizes.

• Journal of the Korean Operations Research and Management Science Society
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• v.17 no.2
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• pp.91-106
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• 1992

It an inventory control system, the demand over time are often assumed to be independently identically distributed (i. i. d.). However, the demands may well be correlated over time in many situations. The estimation of reorder points is not simple for correlated demands with variable lead time. In this paper, a general class of autoregressive and moving average processes is considered for modeling the demands of an inventory item. The first four moments of the lead-time demand (L) are derived and used to approximate the distribution of L. The reorder points at given service level are then estimated by the three approximation methods : normal approximation, Charlier series and Pearson system. Numerical investigation shows that the Pearson system and the Charlier series performs extremely well for various situations whereas the normal approximation show consistent underestimation and sensitive to the distribution of lead time. The same conclusion can be reached when the parameters are estimated from the sample based on the simulation study.