• The Transactions of the Korea Information Processing Society
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• v.2 no.1
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• pp.81-94
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• 1995

By intergrating technologies for protable computers, radio communications, and computer networking, the Land Mobile Computer Network(LMCN) is supposed to overcome the time and space limitation of present computer communication network. However, because the MHs(mobile hosts) do move any time, the network connectivity is often changed causing temporarily duplicated lost, or out-of-sequenced message delivery as well as frequent communications for maintainning the network connectivity. Previous works solved the problems through message flooding, used also in multicasting, resulting in high communication cost(i.e., number of communication messages). In this paper, new protocols for efficient mobility management and multicasting are proposed. The protocols define location update, handover, and multicasting procedure of a MH over a hierarchical LMCN architecture. The protocol specification is presented, and it is shown that the communication cost of the new protocols is superior to the existing ones in terms of the communication cost.

• Journal of KIISE:Information Networking
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• v.36 no.2
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• pp.130-136
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• 2009

Delay and Disruption Tolerant Network (DTN) employs message delivery based on a store-and-forward method to conquer no guarantee of continuous end-to-end connectivity. Different from general networks, it is hard for the existing TCP/IP-based routing protocols to correctly work, due to the characteristics such as large latency and unstable link connectivity. Thus, many recent studies focus on routing protocols for DTN. In this paper, we propose a novel routing protocol for DTN with efficient message delivery utilizing mobility information such as direction or destination of mobile nodes. And this protocol is enhanced in terms of delivery ratio, decreases latency and overhead compared to the previously proposed solutions. Simulation results prove its superiority.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.4
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• pp.781-787
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• 2007

Network Mobility (NEMO) basic support protocol doesn't execute the process of route optimization and has not presented the particular security mechanism in other blocks except hi-directional tunnel between Mobile Router (MR) and its Home Agent (HA). Therefore in this paper we process secure route optimization courses through authenticated binding update protocol between MR and its Correspondent Node (CN) and the protocol of the competency of mandate between MR and its Mobile Network Node (MNN); its block also uses an bi-directional tunnel as the block between MR and its HA. The address of each node are generated by the way of Cryptographically Generated Address (CGA) for proving the ownership of address. Finally we analyze the robustness of proposed protocol using security requirements of MIPv6 and existing attacks and the efficiency of this protocol using the connectivity recovery and end-to-end packet transmission delay time.

• Journal of the Korean Society for Railway
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• v.14 no.4
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• pp.383-389
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• 2011

Until now, in planning and constructing KTX and the Express Way, the connectivity and transfer between these facilities have not been considered. In this study the effect of mode choice behavior by connecting KTX and the Express Way is analyzed through estimating Multinomial Logit Model and Binary Logit Model. The SP and RP surveys to develop these models were carried out and the data were selected from the passengers using the KTX station, Express Bus Terminals and Rest Areas in the Express Way. To test the effect of connectivity and transfer in the field, the case study for Dongtan KTX station was carried out. According to the results, connecting the KTX station and the Express Way has the effect of increasing the demand by 30%. And this is caused by saving about 120 minutes of traveling time from Seoul to Pusan. This study shows that the connectivity and transfer can increase the efficiency of transportation system and the improvement in the mobility and accessibility will maximize the usages of these two facilities.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.5
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• pp.654-666
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• 2019

The tactical network has several different characteristics compared with commercial internet network such as hierarchical topology, dynamic topology changing and wireless link based connectivity. For considering IP mobility management in the tactical network, current mobility management using Mobile IP(MIP) is not suitable with some reasons such as non-optimal routing paths and single point of failure. Proxy Mobile IP(PMIP) which supporting network-based mobility in hierarchical manner can provide optimal routing path in the tactical network environment, but centralized anchor is still remained a threat to the stability of the tactical network which changes its topology dynamically. In this paper, we propose PMIP-based distributed mobility management for the tactical network environment. From our design, routing paths are always configured in optimized way, as well as path is recovered quickly when the mobility anchor of user is failed. From numerical analysis, comparing to other mobility scheme, result shows that the proposed scheme can reduce packet transmission cost and latency in tactical network model.

• International Journal of Advanced Culture Technology
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• v.8 no.1
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• pp.199-206
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• 2020

I suggested the design learning environment based on affordance concept approach for supporting and improving learners' behavior and outcome for convergent design education in this study. The design learning space should be applied teaching and learning activity, especially learners' behavior, physical space condition to support the design thinking process. The design learning space needs openness, individuality and connectivity to support the learners' behavioral to immerse, participate, cooperate, understand, think and fulfill the design thinking process. The composition principles of the learning environment for convergent design education supports communication and collaboration among members for independence and interaction. The spaces for design research and teaching needs high privacy while facilitating visual communications through special materials and wall structure design. Also, for connectivity to improve the learners' physical and visual contact, the environment of the classrooms requires flexibility and mobility by providing an open space integrating unit cells for realizing learning purpose. These are provided by formed of an open structure for inducing visual communication and physical contact to involve the design activities and the mutual interchange.

• The Journal of Information Technology
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• v.9 no.4
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• pp.35-47
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• 2006

Many researches are going on with regard to issues and problems related to mobile database systems, which are caused by the weak connectivity of wireless networks, the mobility and the portability of mobile clients. Mobile computing satisfies user's demands for convenience and performance to use information at any time and in any place, but it has many problems to be solved in the aspect of data management. The purpose of our study is to Implement Real-Time Mobile Query Processing System(MQPS) to solve problems related to database hoarding, the maintenance of shared dataconsistency and the optimization of logging, which are caused by the weak connectivity and disconnection of wireless networks inherent in mobile database systems under mobile client server environments. In addition, we proved the superiority of the proposed MQPS by comparing its performance to the C I S(Client-Intercept-Srever) model.

• Electronics and Telecommunications Trends
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• v.25 no.6
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• pp.38-49
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• 2010

LTE 시스템에서 이동성 관리란 단말의 아이들 상태에서 수행되는 셀 재선택 기능과 단말의 통신중에 수행되는 핸드오버 기능을 모두 포함한다. 특히, 핸드오버 기술은 '통신중 끊김없는 서비스 보장'이라는 단순 기술형태에서 UMTS, HSPA 및 CDMA2000-1X 등 서로 다른 네트워크간의 컨버전스를 통하여 효과적인 트래픽 로드 분산 사업자의 초기 시설투자 부담 감소, 그리고 가입자의 자유로운 네트워크 선택 및 이에 따른 저렴한 요금 혜택 등 사업자와 가입자 모두에게 새로운 비즈니스 모델을 제공하는 복합 기술 형태로 진화되고 있다. 본 고에서는 LTE/LTE-Advanced 시스템에서 무선링크 측정, 타깃 셀 결정, 패킷 손실 관리, 타깃 셀로의 통신로 스위칭 등 일련의 고속 제어절차를 통하여 packet lossless-, timeless- 및 seamless- connectivity가 기능하도록 설계된 핸드오버 기술 전반을 무선 액세스 네트워크 관점에서 다룬다. 본 고에 사용된 정보 소스는 3GPP LTE 표준 문서에 기반한다.

• Journal of Korea Multimedia Society
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• v.10 no.6
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• pp.760-769
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• 2007

In this paper, we consider a group mobility model to formulate a clustering mechanism called Dual Coalescent Energy-Efficient Algorithm (DCEE) which is scalable, distributed and energy-efficient for wireless mesh network. The differences of the network nodes will be distinguished to exploit heterogeneity of the network. Furthermore, a topology control, that is, adjusting the transmission range to further reduce power consumption will be integrated with the cluster formation to improve network lifetime and connectivity. Along with network lifetime and power consumption, clusterhead changes will be measured as a performance metric to evaluate the. effectiveness and robustness of the algorithm.

• Korean Institute of Interior Design Journal
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• v.23 no.4
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• pp.129-139
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• 2014

The objective of this research is to suggest new geometric possibilities in digital architecture by investigating the characteristics of hybridization in digital geometry. The research begins with theoretical background research such as defining hybridization, investigating hybrid thinking, and studying the theory of digital geometry, along with the four conceptual characteristics of hybridization that could be drawn, such as temporality, liquidity, complexity, and connectivity. Based on these characteristics, the generative method of hybrid digital geometric languages such as Blob, Particle, Morph, Loft, and Boolean was analyzed with case research in contemporary digital architecture. As a result, diverse hybrid geometric keywords were extracted; these keywords suggest potential meanings of hybridization such as accidentality, mobility, diversity, and identity. Different elements represent the "mobility" in time by the force and wave, and they are "accidentally" combined in gradual change. The united species in "diverse" characters are seamlessly connected and emerge as a new "identity." The research maximizes the generative possibilities in digital geometry and provides a theoretical basis to apply the digital hybrid methods to architectural design by suggesting the potential meanings and possibilities in hybridization.