• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.5
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• pp.105-111
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• 2008

Mobility support for mobile networks will be important to minimize the packet overhead, to optimize routing, to reduce handoff latency, and to reduce the volume of handoff signals. Mobile IPv6 (MIPv6) and Hierarchical MIPv6 (HMIPv6) are one of mobility management protocols (MMPs) that provides network layer mobility over all access technologies. However, the communication quality of these candidates is severely degraded during handoffs. As another way to improve the handoff performance of a mobile network by conventional MMPs such as MIPv6 and HMIPv6, we propose a Low Latency Handoff Scheme (LLHS) combining Fast MIPv6 (FMIPv6) with HMIPv6 extension with buffering function, in which Mobility Anchor Points (MAPs) buffer packets destined to the Mobile Routers (MRs) or MNs within a mobile network during handoffs. The simulation results show that the proposed scheme reduces transmission delay and packet loss in UDP communication.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.6
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• pp.259-267
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• 2002

In this paper, we focus on comparison and analysis of performance for existing Topology Aggregation algorithm. For these, we designed and implemented PNNI routing simulator which contain various TA schemes, and evaluate performance of TA schemes by this simulator. The PNNI 1.0 specification of the ATM Forum is recommended that hierarchical routing protocol and topology information is aggregated in the network constructed hierarchically Aggregating topology information is known as TA(Topology Aggregation) and TA is very important for scalability and security in network. Therefore, the performance of PNNI network would vary with TA schemes and routing algorithm. PNNI routing simulator can be applied to develope Routing algorithm and TA algorithm and can be develope these algorithms in short period.

• Journal of Internet Computing and Services
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• v.2 no.4
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• pp.1-10
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• 2001

In this paper, we define requirements for call distribution of service control logic in Intelligent Network, Also, we propose call distribution mechanism for every subscriber with different call distribution rates, The call distribution mechanism had been developed as a function of Premium-rate Service in Intelligent Network. Our call distribution mechanism applies to percentage distribution instead of circular or hierarchical distribution. The call distribution mechanism consists of call input. output. call distribution processing logic part, random number generator, and customers database. We propose the practical implementation of a call distribution mechanism and call distribution decision indicating number computation method. We show three methods, the rand() function in C language, microsecond by system clock, and proposed algorithm, to get call distribution decision indicating number. In order to optimal call distribution mechanism, we estimated the results of three methods on occurrence values and the number of occurrences.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.820-823
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• 2011

WSN is composed of a lot of small sensors with the limited hardware resources. In WSN, at the initial stage, sensor nodes are randomly deployed over the region of interest, and self-configure the clustered networks by grouping a bunch of sensor nodes and selecting a cluster header among them. In this paper, we propose a self-configuration routing protocol for WSN, which consists of step-wise ripple routing algorithm for initial deployment, effective joining of sensor nodes. RRA is search node in RF-coverage of each node, which result in fast network connection, reducing overall power consumption, and extending the lifetime of network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.2B
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• pp.76-81
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• 2008

LEACH (Low Energy Adaptive Clustering Hierarchy) has been proposed as a routing protocol with a hierarchical structure, in order to achieve the energy efficiency that is of primary importance in the wireless sensor networks. A wireless sensor network adopting LEACH is composed of a few clusters, each of which consists of member nodes that sense the data, and head nodes that deliver the collected data from member nodes to a sink node that is connected to a backbone network. A head node in a cluster allocates TDMA slots to its member nodes without taking into account whether they have data to transmit or not, thus resulting in inefficiency of energy usage of head node that remains in active mode during the entire round time. This motivates us to propose a scheme to improve the energy efficiency of LEACH, by assigning TDMA slots only to those member nodes who have data to send. As a result, the head node can remain sleep during the period of no data transmission from member nodes, leading to the substantial energy saving. By using the ns-2 simulator, we evaluate the performance of the proposed scheme in comparison with the original LEACH. Experimental results validate our scheme, showing a better performance than original LEACH in terms of the number of outliving nodes and the quantity of energy consumption as time evolves.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.10
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• pp.1435-1440
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• 2021

With the advent of the low interest rate era, many investors are flocking to the stock market. In the past stock market, people invested in stocks labor-intensively through company analysis and their own investment techniques. However, in recent years, stock investment using artificial intelligence and data has been widely used. The success rate of stock prediction through artificial intelligence is currently not high, so various artificial intelligence models are trying to increase the stock prediction rate. In this study, we will look at various artificial intelligence models and examine the pros and cons and prediction rates between each model. This study investigated as stock prediction programs using artificial intelligence artificial neural network (ANN), deep learning or hierarchical learning (DNN), k-nearest neighbor algorithm(k-NN), convolutional neural network (CNN), recurrent neural network (RNN), and LSTMs.

• 한국노년학
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• v.28 no.4
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• pp.1055-1068
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• 2008

Given the central role of sense of control in physical and emotional well-being, the present study examined the determinants of sense of control among Korean elders. We considered sociodemographic characteristics (age, gender, marital status, education, and self-perceived economic status), health-related factors (chronic conditions, functional disability, and sensory impairment), stressful life events, and network-related resources (network of relatives, network of friends, and filial satisfaction) as potential predictors. Sense of control was measured with Pearlin and Schooler's (1978) Mastery Scale. Hierarchical regression analyses with 291 Korean elders aged 60 or older (M age = 69.9) identified lower self-perceived economic status, more chronic conditions, greater functional disability, greater vision impairment, more stressful life events, and lower filial satisfaction as significant risk factors for a diminished sense of control. Because most of the identified risks represent normative experiences during later life, the results underscored the importance of preserving or promoting sense of control for older adults. Implications of the findings and recommendations for future studies are discussed.

• Journal of Korea Trade
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• v.26 no.7
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• pp.59-76
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• 2022

Purpose - As ahigher-order ability, improvisational capability is often employed to help a firm cope with unexpected or unanticipated issues. In light of the severe global business challenges and turbulent environmental changes, this study aimed to explore whether home-based network ties could shape the influence of improvisational capability on international entrepreneurship, alongside investigating the boundary conditions of competitive turbulence in their moderating effects. Design/methodology - The sample for the international entrepreneurship sector was obtained from the Industry and Information Technology Department of Jiangsu. In September 2021, the questionnaires were sent to the targeted ventures and required the top managers to complete the survey by email or telephone. The final research sample comprised 113 international new ventures. To test the hypotheses, moderated hierarchical regression analysis was conducted. Findings - Our empirical results suggested that (1) unlike some previous literature, a positive effect of improvisational capability on the performance of international new ventures was not found; (2) home country-based networks (both political ties and business ties) are contingent factors that may partially stimulate the value creation of improvisational capability; and (3) in a highly competitive environment, the moderating role of business ties at home may become much stronger, however, the contingent role of political ties at home was not found. Originality/value - This study mainly concentrates on the two important types of home country-based networks, political and business ties at home, that may help international new ventures access strategic resources necessary for supporting the performance implications of improvisational capability. Thus, it extends the existing improvisational theory to encompass international entrepreneurship.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.1 s.343
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• pp.103-110
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• 2006

Internet engineering task force (IETF) has proposed hierarchical mobile IPv6 (HMIPv6) in order to reduce a frequent location registration of a mobile node in mobile IPv6 (MIPv6). All traffics toward a mobile node must be transmitted through a MAP in HMIPv6. This brings unnecessary packet latency because of the increased processing cost of packet at the MAP. At this point the processing cost of packet at the MAP is influenced by the packet arrival rate for a mobile node and the number of mobile nodes in MAP domain. In this paper, we propose that MIPv6 and HMIPv6 are adaptively selected to minimize signaling coast of network as complementing weak point of MIPv6 and HMIPv6. After suppose that the packet arrival rate for a mobile node is fixed ,with this in mind, we find the optimal number of mobile nodes compared the total cost of HMIPv6 with the total cost of MIPv6. And if Mobile Nodes that the MAP is able to manage is full in MAP domain, a mobile node entering MAP domain is provided connection by MIPv6 instead of HMIPv6. In the conclusion, the proposed method of this paper shows that the weak points of MIPv6 and HMIPv6 are removed by adaptive selecting each other.

• Journal of Internet Computing and Services
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• v.19 no.1
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• pp.37-47
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• 2018

The number of capabilities of Internet of Things (IoT) devices will exponentially grow over the next years. These devices may generate a vast amount of time-constrained data. In the context of IoT, data management should act as a layer between the objects and devices generating the data and the applications accessing the data for analysis purposes and services. In addition, most of IoT services will be content-centric rather than host centric to increase the data availability and the efficiency of data delivery. IoT will enable all the communication devices to be interconnected and make the data generated by or associated with devices or objects globally accessible. Also, fog computing keeps data and computation close to end users at the edge of network, and thus provides a new breed of applications and services to end users with low latency, high bandwidth, and geographically distributed. In this paper, we propose Edge-Fog cloud-based Hierarchical Data Delivery ($EFcHD^2$) method that effectively and reliably delivers IoT data to associated with IoT applications with ensuring time sensitivity. The proposed $EFcHD^2$ method stands on basis of fully decentralized hybrid of Edge and Fog compute cloud model, Edge-Fog cloud, and uses information-centric networking and bloom filters. In addition, it stores the replica of IoT data or the pre-processed feature data by edge node in the appropriate locations of Edge-Fog cloud considering the characteristic of IoT data: locality, size, time sensitivity and popularity. Then, the performance of $EFcHD^2$ method is evaluated through an analytical model, and is compared to fog server-based and Content-Centric Networking (CCN)-based data delivery methods.