• Journal of the Korea Institute of Building Construction
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• v.7 no.4
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• pp.109-116
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• 2007

Building structures are generally large in size and have a long life, and the construction of such structures requires the investment of a huge amount of money and social infrastructure. Furthermore, building structures are closely related to people's life. Recently, however, the rapid development of society has been worsening air pollution, which is in turn accelerating the degradation of building structures. Thus, the safety of building structure is emerging as a critical issue. To cope with this problem, the government enacted "The Special Act on Safety Control for Infrastructure" but we need engineers' higher concern over the maintenance and reinforcement of existing structures. Recently researches are being made actively on repair mortar using ultra rapid hardening cement for recovering the performance of structures. The present study conducted an experiment on the basic physical properties of ultra rapid hardening mortar for repairing and reinforcing building structures using magnesia cement and mono-ammonium phosphate. In the experiment, we changed the water-cement ratio and carried out replacement at different ratio of MAP/MgO(%). We used retarder to have working life, and made comparative analysis through evaluating working life and fluidity and measuring strength by age.

• Research in Community and Public Health Nursing
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• v.14 no.4
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• pp.587-597
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• 2003

Purpose: The purpose of this study was to estimate the demand and supply of visiting nursing services provided by health centers in urban area, aiming at strengthening infrastructure, which may improved the quality of life and health status of vulnerable population in the community. Methods: This study was conducted through nominal group discussion, focus group study. The demand and supply of visiting nursing were estimated by health economists based on the secondary analysis data from 25 health centers in Seoul. Result: Primary targets for the visiting nursing must be people who are homebound in the community. They can be classified into: a group of Level I: chronic patients who need visiting nursing care at least once a week: and a group of Level II: vulnerable families that need management periodically e. g. twice a month. Based on the estimation of demand for visiting nursing services in the community, the estimated supply required was $651{\sim}770$ visiting nurses including home health nurses in visiting nursing programs based on health centers in Seoul. Conclusions: The estimated demand and supply of visiting nursing are expected to provide basic data for establishing alternative policies on visiting nursing infrastructure that might be accomplished through demand-based visiting nursing programs by districts.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.3
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• pp.515-524
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• 2010

Recently, many actions are taking to accelerate progress toward social consensus and implementation of Smart Grid. Smart Grid refers to a evolution of the electricity supply infrastructure that monitors, protects, and intelligently optimize the operation of the interconnected elements including various type of generators, power grid, building/home automation system and end-use consumers. The most distinguished element will be Advanced Metering Infrastructure (AMI) that will be installed to every end-use consumer's home or building and optimize the energy consumption of the end-use consumer. The key function of AMI is energy management capability that coordinates and optimally controls the various loads according to the operating condition and environments. In this study, we figure out the basic function of AMI in Smart Energy House that can be defined as a model house implementing in Smart Grid. This paper proposes the energy management algorithm that will be implemented in AMI at Smart Energy House. The paper also show how energy saving in Smart Energy House can be achieved applying the proposed algorithm to an actual house model that has mainly lighting, air-conditioning, TV loads.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.6
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• pp.47-54
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• 2016

This study is a basic research on the functional performance review for the use of environmentally friendly construction materials as lapilli-bio block. The neutralization processed Mt. Backdusan and Mt. Hallasan lapilli-bio block were identified vegetation characteristics and water purification properties. As a result, the adsorption of root was more favorable, depending on the material properties of many voids Lapilli. And if the neutralization processed lapilli-bio blocks maintain a long-term immersion conditions in contaminated water was found to be expected from the improvement effect of SS, T-N and T-P. However, field trials and continuous studies are expected to be identified by the use of lapilli-bio block.

• Journal of KIISE:Information Networking
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• v.30 no.6
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• pp.714-719
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• 2003

A Mobile IPv6 services exposes its vulnerability when a mobile node is roaming the subnets belonging to the different domains. The AAA infrastructure is strongly recommended when the ISPs need to authenticate the mobile user comes from the different domains. In addition to the basic requirements for the AAA service, the authentication latency and AAA message overhead should be minimized for the continuity of the mobile service. This paper considers the roaming service with AAA infrastructure in Mobile IPv6 and proposes an authentication scheme using delegation to authenticate the mobile node with effective manner. The effectiveness of the proposed scheme is confirmed using the cost analysis. The result shows at least 50% of performance enhancement when the MN is roaming fast under the control of the delegation.

• Journal of Arbitration Studies
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• v.9 no.1
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• pp.367-390
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• 1999

The basic requirements for conducting electronic commerce include confidentiality, integrity, authentication and authorization. Cryptographic algorithms, make possible use of powerful authentication and encryption methods. Cryptographic techniques offer essential types of services for electronic commerce : authentication, non-repudiation. The oldest form of key-based cryptography is called secret-key or symmetric encryption. Public-key systems offer some advantages. The public key pair can be rapidly distributed. We don't have to send a copy of your public key to all the respondents. Fast cryptographic algorithms for generating message digests are known as one-way hash function. In order to use public-key cryptography, we need to generate a public key and a private key. We could use e-mail to send public key to all the correspondents. A better, trusted way of distributing public keys is to use a certification authority. A certification authority will accept our public key, along with some proof of identity, and serve as a repository of digital certificates. The digital certificate acts like an electronic driver's license. The Korea government is trying to set up the Public Key Infrastructure for certificate authorities. Both governments and the international business community must involve archiving keys with trusted third parties within a key management infrastructure. The archived keys would be managed, secured by governments under due process of law and strict accountability. It is important that all the nations continue efforts to develop an escrowed key in frastructure based on voluntary use and international standards and agreements.

• Journal of IKEEE
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• v.20 no.4
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• pp.367-372
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• 2016

We Designed and Conduct a study on the basic intrusion detection research for outside intruder, which can determine the location and the weight of an intruder into infrastructure, by using Fiber-Optic ROTDR( Rayleigh Optical Time Domain Reflectometer) sensor, which are buried in the sand, were prepared to respond the intruder effects. The signal of ROTDR was analyzed to confirm the detection performance. The weight could be detected as 4 grades, such as 20kg, 40kg, 60kg, and 80kg. which used long distance fiber for intruder detection on wide area. This sensor was possible for application of real-time monitoring of infrastructures.

• The Journal of the Korea Contents Association
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• v.6 no.3
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• pp.28-37
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• 2006

In the last decades, inter-networking technologies advanced more rapidly than any other field. Today, the Internet is one of the most important infrastructure to society as becoming an indispensible tool of people and companies. During mid-1990's, developed countries recognized the advanced network as a basic infrastructure for the future science and technology development. They developed national research and education networks for the development of future science and network technology. In this paper, we made a comprehensive review of global research and education network developments. We also made analysis of Korea's activities on advanced network comparing with those of developed nations, then suggested approaches to improve Korean advanced networks.

• International Journal of High-Rise Buildings
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• v.6 no.4
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• pp.327-332
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• 2017

This paper discusses several topics associated with the densification caused by supertall buildings and their impact on city systems. The paper covers five key areas where a supertall tower creates a concentration of needs and effects. First, the paper comments on population shifts towards the city and how they affect carbon footprint, utilities infrastructure and transport. The effect of single- and mixed-use towers is discussed in the context of population density. The second section brings the issues of transit, accessibility and master planning into focus. The use and criticality of public transport, cycling and walking is described. Servicing and deliveries using freight consolidation and shared systems is also discussed along with their contribution to the culture of sustainable travel. In the third section the paper reflects on supertall buildings' below-ground utilities and drainage provision, particularly the challenges faced in established city infrastructures. The utilities issues associated with supertall concentration (in land-use terms) compared to equivalent low-rise distribution is also commented on in the context of surface water runoff. In the fourth section, the topic of supertall sustainability is discussed and how city systems need to respond to create desirable and affordable space for occupiers. The changing need for vertical communities, 'stacked neighbourhoods' and the notion of a micro-city is described. Finally, the paper considers the energy consumption and resilience of supertall buildings in the context of basic geometry, façade design, climate and mixed-use benefits as they impact city systems.

• International Journal of High-Rise Buildings
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• v.8 no.4
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• pp.303-311
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• 2019

The effectiveness of aerodynamic modification to reduce wind loadings has been widely reported. However, most of previous studies have been investigated dynamic forces and pressure distributions on tall buildings with various unconventional configurations. This study was investigated dynamic characteristics and aerodynamic instability of super-tall buildings with unconventional configurations through extensive aeroelastic model experiments. Seventeen types of supertall building models were considered such as basic and corner modification with corner cut, chamfered, oblique opening, tapered, inversely tapered, bulged, helical with twist angles of $90^{\circ}$, $180^{\circ}$, $270^{\circ}$, $360^{\circ}$ and composite with $360^{\circ}$ helical & corner cut, 4-tapered & $360^{\circ}$ helical & corner cut, setback & corner cut, setback & $45^{\circ}$ rotate. As a result, aerodynamic characteristics of helical models with single modification are superior to those of other models with single modification. However, effect of twist angle for helical model is negligible. Further, the 4-tapered & $360^{\circ}$helical & corner cut model is most effective in reducing the along- and across-wind fluctuating displacement responses in all of experimental models.