• Journal of KIISE:Databases
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• v.33 no.3
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• pp.271-281
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• 2006

Recently the need for Location-Based Service (LBS) has increased due to the development and widespread use of the mobile devices (e.g., PDAs, cellular phones, labtop computers, GPS, and RFID etc). The core technology of LBS is a moving-objects database that stores and manages the positions of moving objects. To search for information quickly, the database needs to contain an index that supports both real-time position tracking and management of large numbers of updates. As a result, the index requires a structure operating in the main memory for real-time processing and requires a technique to migrate part of the index from the main memory to disk storage (or from disk storage to the main memory) to manage large volumes of data. To satisfy these requirements, this paper suggests a unified index scheme unifying the main memory and the disk as well as migration policies for migrating part of the index from the memory to the disk during a restriction in memory space. Migration policy determines a group of nodes, called the migration subtree, and migrates the group as a unit to reduce disk I/O. This method takes advantage of bulk operations and dynamic clustering. The unified index is created by applying various migration policies. This paper measures and compares the performance of the migration policies using experimental evaluation.

• Journal of KIISE:Databases
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• v.35 no.3
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• pp.272-285
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• 2008

In this paper, we concentrate on data allocation methods for multiple broadcast channels. When the server broadcasts data, the important issue is to let mobile clients access requested data rapidly. Previous works first sorted data by their access probabilities and allocate the sorted data to the multiple channels by partitioning them into multiple channels. However, they do not reflect the difference of access probabilities among data allocated in the same channel. This paper proposes ZGMD allocation method. ZGMD allocates data item on multiple channels so that the difference of access probability in the same channel is maximized. ZGMD allocates sorted data to each channels and applies Broadcast Disk in each channel. ZGMD requires a proper indexing scheme for the performance improvement. This is because in ZGMD method each channel got allocated both hot and cold data. As a result, the sequential search heuristic does not allow the mobile client to access hot data items quickly. The proposed index scheme is based on using dedicated index channels in order to search the data channel where the requested data is. We show that our method achieve the near-optimal performance in terms of the average access time and significantly outperforms the existing methods.

• International Commerce and Information Review
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• v.18 no.2
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• pp.27-51
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• 2016

The purpose of this paper is to examine correlations between the facilitating factors of the B2C e-commerce and the online shopping and the overseas direct purchase for the purpose of suggesting the successful logistics operational strategies for the domestic parcel delivery service companies. This paper conducts wide literature reviews and empirical analyses on relationships between the facilitating factors of B2C e-commerce and the online shopping and the overseas direct purchase in B2C e-commerce. We built two regression equations that dependable variables are the turnover of online shopping and the amount of imports by international postal logistics services respectively. The former equation's estimation results show that all the independable variables are affecting the dependable variable in the long-term jointly. And, the results show that the change of the turnover of online shopping is affected not only by the change of the usage count of a credit card and the real GDP, but also by the change of the error-correction variable. The latter equation's estimation results show that all the independable variables are affecting the dependable variable in the long-term jointly. Futhermore, the results show that the change of the amount of imports by international postal logistics services is affected not only by the change of the usage count of a credit card, the exchange rate and the internet protocol IPv4, but also by the change of the error-correction variable. Based on these research results, a high advanced strategic approach for optimum parcel delivery services is highly required.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.1
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• pp.51-63
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• 2013

Recently with base apply MANET with the application for the service discovery and delivery which are various techniques are being proposed the result of such MANET base research techniques from actual inside. This dissertation proposes T-Chord(Trustworthy-based Chord) Ring system for MANET to guarantees from such requirements. T-Chord Ring system in order to manage Efficiently the services which the mobile nodes provide is the service discovery system which uses P2P overlay network Technique in mobile environment. The system which is proposed MANET communications in order to accomplish a service discovery operation with physical network class and logical network class will be able to minimize problems from about MANET service discoveries, and uses the dispersive hash table technique for a service discovery and effectiveness of service discovery improves and will be able to guarantee the expandability of network size. The mobile nodes(mobile device) have a mobility from MANET and operate with service request node, service provide node and service transmit node. The mobile nodes will be able to elect cluster header using Trustworthy that was evaluated service request, provision and delivery in each other. The system which is proposed a service discovery and a delivery efficiently will compose the cluster head which will grow of P2P overlay networks and will be able to accomplish. The system which proposes from dissertation is composed of Trustworthy evaluations of MANET mobile nodes, service information collection which is dispersed and P2P overlay networks that composed of Chord algorithm modules which provide O(Log N) efficiencies. The system comparison evaluation analyzes an efficiency from the expandability side of effectiveness and the network of service discovery technique and the service discovery message over head, service discovery and delivery of former times and service discovery and delivery is excellent gives proof from MANET.

• Journal of Digital Contents Society
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• v.19 no.3
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• pp.505-512
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• 2018

Internet demand has increased rapidly, and Internet Protocol Version 4, the main Internet protocol, can not cope with various types of network demand in the future. Therefore, it is urgent to spread IPv6-based stable network to solve the shortage of Internet address resources. Due to the proliferation of IoT and the increase in mobile devices, efficient and optimal IPv6 routing design is indispensable. In this paper, we have studied about characteristics of IPv6, address system of IPv6, structure analysis and efficient routing technology among IPv6 terminals. Furthermore, experimental results on routing packet analysis and convergence time are presented in network - based IPv6 routing implementation environment. In addition, we show the results of the experiment analysis by dividing the implementation of IPv6 routing, operation test, and fail over performance into three kinds of routing protocol methods. As a result, this study can be applied to the introduction of IPv6 system, test bed environment construction, and network design.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.11
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• pp.2661-2667
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• 2013

Recently, at Home and abroad, Internet of Things era things(Thing) is participating as a subject of communication in human communication paradigm of existing (lot/M2M) is in full swing. Automobile, refrigerator, bicycle, until shoes, and communication functions generation of information is installed and has created a fusion of new service IT infrastructure. Its use and application are broadening to various areas and the number of devices used for it is increasing to increase the number of information transmitted for each object. When the traffic reaches its limit while each set of data is transmitted from the devices divided into each group through the mobile network, M2M communications service might not be processed smoothly. This study used the Knapsack Problem algorithm to create a virtual simulator for a smooth M2M service when the mobile network used for the M2M communications reaches its limit. The virtual simulator applies smooth processing of services from the M2M communications that should be processed first to other subsequent services when data comes to each group of devices. As the M2M technology develops to make many objects more compact in size, it would help with smoother processing of M2M services for the mobile network with fast-increasing traffic.

• 한국HCI학회:학술대회논문집
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• 2008.02b
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• pp.239-244
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• 2008

We lead a life in our community, beginning a new relationship with a stranger or maintaining or stopping existing relationships. Relationships with others are sustained through social activities based on communication. Generally speaking, by exchanging feelings and information through communication, relationships are formed and continued, and strengthened through active communication As a result of the development of technologies and information technology over the recent 10 years, a mobile phone has stood as a communication channel, and now it has become such a universal, and highly intimate and important means of communication that almost all the Koreans use more often than wired phones. Today, people have their communication channel available for others, by using a mobile phone at any time and anywhere. Like this, mobile phones have been playing a key role in helping people maintain, repair and strengthen their personal relationship, but from the perspective of personal relationship management, they still remain as an aid to help communication, failing to provide a positive help for actual relationship management. This study was designed to provide services supporting user's personal relationship management, focusing on the use of mobile phones as a major tool of communication, aiming to enable users to understand current state of their relationship and make relationship management efforts, or communication behaviors, by informing who needs communication, on the basis of data on mobile phone calls. To this end, the study established a method to extract intimacy between users and callers and develop a prototype of services supporting personal relationship management, using relationship characteristics in terms of mobile communication.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.1
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• pp.84-91
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• 2011

To develop the new network, the future network architecture is studied. Since the mobile devices are also advanced, they need for the mobility protocols. The one of the protocols, Fast handovers for proxy MIPv6(PFMIPv6) has studied by the Internet Engineering Task Force(IETF). Since PFMIPv6 adopts the entities and the concepts of fast handovers for MIPv6(FMIPv6) in proxy MIPv6(PMIPv6), it reduces the packet loss. Although the conventional scheme has proposed that it cooperated with an Authentication, Authorization and Accounting (AAA) infrastructure for authentication of a mobile node in PFMIPv6, it has the drawbacks such as high signaling cost and long handover latency. To reduce the signaling cost and the handover latency, we propose an enhanced authentication scheme in Fast handover for Proxy MIPv6. The proposed scheme reduces the handover latency and the signaling cost because the registration procedure and the authentication procedure are simultaneously performed. We also compare the proposed scheme with the conventional scheme in terms of the signaling cost and the handover latency.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.1
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• pp.31-39
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• 2014

For mobile application, semiconductor packages are increasingly moving toward high density, miniaturization, lighter and multi-functions. Typical wafer level packages (WLP) is fan-in design, it can not meet high I/O requirement. The fan-out wafer level packages (FOWLPs) with reconfiguration technology have recently emerged as a new WLP technology. In FOWLP, warpage is one of the most critical issues since the thickness of FOWLP is thinner than traditional IC package and warpage of WLP is much larger than the die level package. Warpage affects the throughput and yield of the next manufacturing process as well as wafer handling and fabrication processability. In this study, we investigated the characteristics of warpage and main parameters which affect the warpage deformation of FOWLP using the finite element numerical simulation. In order to minimize the warpage, the characteristics of warpage for various epoxy mold compounds (EMCs) and carrier materials are investigated, and DOE optimization is also performed. In particular, warpage after EMC molding and after carrier detachment process were analyzed respectively. The simulation results indicate that the most influential factor on warpage is CTE of EMC after molding process. EMC material of low CTE and high Tg (glass transition temperature) will reduce the warpage. For carrier material, Alloy42 shows the lowest warpage. Therefore, considering the cost, oxidation and thermal conductivity, Alloy42 or SUS304 is recommend for a carrier material.

• The Journal of the Korea Contents Association
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• v.12 no.5
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• pp.103-112
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• 2012

This paper is based on the perspective that the YTN Science, a science channel in Korea which plays a key role in the popularization of science, is suffering from low viewing ratings, insufficient content, and shortage of production. First, this study employs an exploratory method to identify current status of programming and operation of the Korean science channel along with its promotional strategy. Second, it aims to conduct an analysis on the science channels, specifically some major programs, of other nations including the U.S. (Discovery Channel, National Geographic Channel), United Kingdom (BBC Knowledge), Japan (Science Channel), and China (CCTV 10), seeking the possibility to apply and combine them afterward to the Korean TV channels specialized in science. A number of implications are derived from our diagnosis of present situation and analysis of abroad cases, and this helps us suggest the content development and promotional strategies as follows: First, due to the rising need for change in the programming strategy to enhance the value of the content, it is required to rearrange the programming in terms of the target audience and the viewer lifestyle, adopt a new strategy for building up the viewers' watching habit through 'stripping', and place strategic programs in prime-time. Second, as for the specific schemes of content production and application, it is recommended to establish a dual strategy in creating the content (one for conveying knowledge, the other for delivering fun), plan and use a representative character of the program, select scientific and technological topics with more Korean backgrounds, attempt strategic ties with SNS, deepen and diversify the material for programs, and implement a strategy to boost the OSMU. Finally, with regard to the promotional strategy, a constructive proposal may include raising channel awareness through science-related events and live broadcasting, performing promotional strategies by way of expanding to printed media like magazine and book publications, and intensifying online and mobile promotional strategy.