• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.8B
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• pp.1444-1455
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• 1999

In the standard location strategy such as IS-41 and GSM, Home Location Register(HLR) and Visitor Location Register(VLR) databases are used to manage the location of mobile terminals. The primary goal that location management schemes investigate is to reduce the cost of database access and the traffic for signaling network. When mobile terminals move frequently, one of problems in the standard location management scheme is that HLR database is highly updated and the traffic in signaling network can be occurred significantly due to high message transfer rate between HRL and VLR. As a solution to these problems, this paper proposes the location management scheme using VLR Gateway(VG) to reduce the both traffics of HLR update and signaling network which are resulted from location registration requirements of mobile terminals whenever they cross their registration area boundary. VG is a kind of database that is placed between HLR and VLR. It integrates one or more registration area defined in a system into one group and plays a role on behalf of HLR in a integrated registration scope so that the call delivery and the movement of mobile terminals are possible without HLR access in the scope. In order to evaluate performance of IS-41 and proposed scheme, we simulate two schemes based on wide range of call to mobility ratio. Its experiment result shows that in the proposed scheme total database cost increased slightly whereas HLR and signaling traffic decreased remarkably.

• The KIPS Transactions:PartC
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• v.12C no.7 s.103
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• pp.1031-1038
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• 2005

As the research on home network technologies, sensor network technologies, and ubiquitous network technologies makes rapid progresses, wireless ad-hoc network have attracted a lot of attention. A wireless ad-hoc network is a temporary network formed by a collection of wireless mobile nodes without the aid of my existing network infrastructure or centralized administration, and it is suitable for ubiquitous computing environments. In this paper, we suggest an interconnection scheme between the wireless ad-hoc network environment based on multiple path source routing protocol and a Mobile-IP based network environment. This scheme reduces the overhead of route re-establishment and re-registration by maintaining multiple paths between the mobile host in wireless ad-hoc network and the base station in mobile-IP network. Also it puts the base station in charge of function that performs translation between wireless ad-hoc network packets and Mobile-IP packets, reducing the load of mobile hosts. In this paper, our simulations show that our scheme outperforms existing interconnecting schemes with regards to throughput and end-to-end delay Also we show that our scheme outperforms multi-paths approach using disjoint routes with regards to routing overhead.

• 한국HCI학회:학술대회논문집
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• 2008.02b
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• pp.456-459
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• 2008

We are now in the era of digital convergence with CE products and PC at the center, but product diversification occurs in the same breath. Each device may perform its own functions itself independently, but proportion of the inter-device usage is increasing gradually by concept of a home network and ubiquitous widely prevailed. The consumer's need of inter-device connection will take the dominative position of the market. Therefore, we can easily forecast that diversification of the products may inevitably lead connectivity patterns complicated considering recent market situation and trends. In this paper, we propose the methodology for designing inter-device connectivity which covers issues such like segmenting numerous number of connectivity pattern, and establishing their structure of control. Our methodology also supports the inter-device connection with extensive latitudes and a multi-device simultaneous control. In order to present inter-device connectivity guideline, we define four stages of a user experience - Connection, Configuration, Use, Disconnection. Based on the 4 user experience stages, we suggest a specific connectivity designing guideline for each step.

• Journal of the Korea Concrete Institute
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• v.25 no.1
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• pp.53-61
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• 2013

A new deformation of reinforcing bar in coils was proposed to improve a machinability of straightening process, which has crescent-shaped transverse ribs with an inclination angle of 50 degrees, a crest width of $0.15d_b$, and a flank inclination of 55 degrees. The proposed deformation can increase contact area between a surface of re-bar and a groove of a roller during a straightening process and, therefore, it might reduce a damage of ribs, improve a final straightness, and enhance an efficiency of the straightening process. Splice tests were conducted to evaluate bond strengths of three types of re-bar in coils including the proposed re-bar, of which the inclination angles of transverse ribs were 50, 60, and 90 degrees, respectively. Test results show that the re-bars in coils have higher bond strengths than predicted strengths by equations of Orangun et al., ACI 408, and KCI by at least 10%. Correlation coefficients of bond strengths between a straight bar and re-bars in coils are 0.94 and more. Consequently, equations of the KCI code for determining development and splice lengths can be applied to the tested re-bars in coils.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.5
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• pp.41-48
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• 2005

OSGi(Open Service Gateway Initiative) offers a unique opportunity for pervasive computing as a potential framework for achieving interoperability between various sensors, home appliances, and networked devices. The OSGi framework supports a remote installation of a bundle, which is a unit that installs and deploys services. However, in order for the bundle in execution to migrate, a specific form of bundle such a mobile agent, is needed one which is able to move through a heterogeneous network. This paper proposes a method that can manage bundles like these dynamic agents, in order to ensure the mobility of entities in multiple OSGi framework environments. For our purposes, we have designed the mobile agent management system for managing the lifecycle and mobility of agents in the OSGi framework. The mobile agent management system we are proposing implements a bundle form which can perform in an OSGi framework as well as manage autonomous mobile services. As a result, mobility in a pervasive environment will be supported more efficiently.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.10 no.1
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• pp.199-210
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• 2015

This study analyzes various aspects of the successful overseas expansion of SMEs that export consumer goods with their own brands. Through in-depth interviews with CEOs and marketing practitioners of fifteen SMEs that export consumer goods of their own brands, researchers examined the determinants of the decisions to export own-brand products, forms of expansion into foreign markets, firms' distribution networks, firms' technological and marketing capabilities, export barriers, and export support services offered by the government. The results indicate that these companies obtained competitiveness in the design and quality of their products through steady R&D investment, with a focus on niche markets. This study also shows that they established foreign branches, participated in overseas trade fairs, and tapped into foreign markets with Korean home shopping channels and department stores to build distribution channels and to find new buyers. However, the findings of this study reveal that many of those companies export both OEM/OEM products as well as their own-brand products due to the low level of brand awareness in foreign markets. Thus, efforts to improve their brand awareness in the global market are much needed. In addition, this paper demonstrates that the programs and services provided by state-run organizations need improvement in credibility and expertise. This research suggests recommendations for successful export programs, and provides meaningful insights for consumer-goods SMEs establishing foreign market entry strategies with their own brands.

• Communications of Mathematical Education
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• v.34 no.1
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• pp.1-15
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• 2020

Today's healthcare, intelligent robots, smart home systems, and car sharing are already innovating with cutting-edge information and communication technologies such as Artificial Intelligence (AI), the Internet of Things, the Internet of Intelligent Things, and Big data. It is deeply affecting our lives. In the factory, robots have been working for humans more than several decades (FA, OA), AI doctors are also working in hospitals (Dr. Watson), AI speakers (Giga Genie) and AI assistants (Siri, Bixby, Google Assistant) are working to improve Natural Language Process. Now, in order to understand AI, knowledge of mathematics becomes essential, not a choice. Thus, mathematicians have been given a role in explaining such mathematics that make these things possible behind AI. Therefore, the authors wrote a textbook 'Basic Mathematics for Artificial Intelligence' by arranging the mathematics concepts and tools needed to understand AI and machine learning in one or two semesters, and organized lectures for undergraduate and graduate students of various majors to explore careers in artificial intelligence. In this paper, we share our experience of conducting this class with the full contents in http://matrix.skku.ac.kr/math4ai/.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.4
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• pp.429-440
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• 2015

In this study, model test equipment was developed to evaluate the hydraulic pressure reduction in appling the drainage shield tunnel and the model test for hydraulic pressure difference was performed in case of drainage and undrained conditions. In the result of model test, increase ratio of pore water pressure was decreased in drainage condition and total stress in drainage condition was smaller than that in undrained condition, so the hydraulic pressure was reduced by the groundwater inflow into the model tunnel. In the result of field instrumentation, the hydraulic pressure in the back ground of shield tunnel was small by 11~22% in comparison with the calculated hydraulic pressure ($r_w{\cdot}H$) in same groundwater level. In the result of model test and field instrumentation, it was appeared in drainage and undrained conditions that the difference between the theoretical hydraulic pressure and the real hydraulic pressure. It shows that it is possible to apply the reduced hydraulic pressure in applying the drainage shield tunnel and to reduce the segment section due to hydraulic pressure reduction.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.10
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• pp.137-147
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• 2007

In the host-based Mobile IPv6, a mobile node is responsible for doing the signaling to its home agent to enable session continuity as it moves between subnets. To remove the mobile node's signalling processing load, the network-based Mobile IPv6 has been proposed recently. It allows session continuity for a mobile node without its involvement in mobility management. The proxy mobility agent in the network performs the signaling and does the mobility management on behalf of the mobile node. However, to make secure communications for a mobile node, security mechanisms against diverse attacks should be adopted. To do this, first of all security threats to the network-based Mobile IPv6 should be also identified and analyzed. Potential attack objectives may be to consume network services at the cost of a legitimate mobile node and, eavesdropping and fabrication of user traffic through interception of a mobile node's communications. This paper identifies and discusses security threats to the network-based Mobile IPv6 in details. The results of threats analysis are limited to threats that are peculiar to the network-based Mobile IPv6 except threats to IPv6 in general.

• Journal of Korea Port Economic Association
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• v.36 no.1
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• pp.129-140
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• 2020

In the future, the global container handling market will be reorganized into larger ships and shipping alliances, and the bargaining power of shipping companies will be further strengthened. Therefore, the global terminal operator (GTO), which has a global network, vast experience, and operational know-how, is expected to strengthen its competitiveness. In Korea, the central government promoted the development of GTOs in the mid-2000s, but it failed, mainly due to disagreements between port stakeholders. In this study, the macroeconomic indicators that have the same effect in all regions were used to analyze GTO management performance. In the short term, it could be used to establish the business strategy of domestic terminal operators based on changes in macroeconomic indicators. In the long term, it would be used to establish a promotion strategy for GTOs in Korea. The results of analyzing the impact of macroeconomic indicators on the GTO's profit show that the GTO's profit is significantly affected by cargo handling capacity, the consumer price index of the United States, the Shanghai Composite Index, the Crude Oil Price, and the London Inter-bank Offered Rate (LIBOR). However, the scale of impact was not significantly different between public and private GTOs.