• Earthquakes and Structures
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• v.14 no.2
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• pp.103-115
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• 2018

In this work, a simple but accurate hyperbolic plate theory for the free vibration analysis of functionally graded material (FGM) sandwich plates is developed. The significant feature of this formulation is that, in addition to including the shear deformation effect, it deals with only 3 unknowns as the classical plate theory (CPT), instead of 5 as in the well-known first shear deformation theory (FSDT) and higher-order shear deformation theory (HSDT). A shear correction factor is, therefore, not required. Two common types of FGM sandwich plates are considered, namely, the sandwich with the FGM face sheet and the homogeneous core and the sandwich with the homogeneous face sheet and the FGM core. The equation of motion for the FGM sandwich plates is obtained based on Hamilton's principle. The closed form solutions are obtained by using the Navier technique. The fundamental frequencies are found by solving the eigenvalue problems. Numerical results of the present theory are compared with the CPT, FSDT, order shear deformation theories (HSDTs), and 3D solutions. Verification studies show that the proposed theory is not only accurate and simple in solving the free vibration behaviour of FGM sandwich plates, but also comparable with the higher-order shear deformation theories which contain more number of unknowns.

• Journal of Auto-vehicle Safety Association
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• v.7 no.2
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• pp.15-18
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• 2015

The availability of in-depth accident data is a prerequisite for each efficient traffic safety management system. Identification and definition of the relevant problem together with knowledge of the data and parameters describing this problem is essential for its successful solution. Comprehensive, up-to-date, accident data is needed for recognition of the scope of road safety problems and for raising public awareness. Reliable and relevant data enable the identification of the contributory factors of the individual accidents, and an unveiling of the background of the risk behaviour of the road users. It offers the best way to explore the prevention of accidents, and ways to implement measures to reduce accident severity. In this study, reviewing the existing iGlad and GIDAS system, KIDAS data format can be finalized through feasibility evaluation. The progressive approach is proposed to successful settlement of Korea in-depth accident study. As the initial stage of in-depth investigation DB construction, the KIDAS is not repetition of the current police based TAAS. It is essential part of improving vehicle safety and reduction of traffic fatality in Korea. 72 Contributing factors like road and traffic characteristics, vehicle parameters, and information about the people involved in the accident have to be investigated and registered as well in the KIDAS.

• Journal of Korean Library and Information Science Society
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• v.35 no.1
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• pp.187-213
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• 2004

Nowadays changes of financial environment are internalization, generalization and autonomous system. The most importance in a struggle for existence is to secure a customer. The purpose of this study is to analyze whether information on financial service accounts have fully offered over internet, which information consumers needed in buying financial service accounts and whether consumer have satisfied with offered information Through this, to enhance the efficiency of financial information offered to consumer over internet and to explore the consumer demanding information model by finding the problems of offering financial information. The specific purpose of this study me following; 1. to investigate the actual situation which consumers behaviour of information providing and choosing about financial accounts items on internet. 2. to analyze the relationship between the level of consumer information need about financial information and rotated variables. 3. to analyze the relationship between the level of consumer information satisfaction about financial information over internet and related variables. 4. to analyze the new information financial service and contents. 5. to analyze the informatic information and financial service accounts.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.4
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• pp.449-459
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• 2000

The original Mindlin-type degenerated shell element perform reasonably well for moderately thick shell structures. However, when full integration for analysis of thin shell is used to evaluate the stiffness matrix, the stiffness of shell element is often over-estimated due to shear or membrane locking phenomena. To correct this problem, the formulation of the new degenerated shell element is derived by the combination of two different techniques. The first type of elements(TypeⅠ) has used assumed shear strains in the natural coordinate system to overcome the shear locking problem, the reduced integration technique in in-plane strains(membrane strains) to avoid membrane locking behaviour. Another element(TypeⅡ) has applied the assumed strains to both of membrane strain and transverse shear strains. The improved degenerated shell element has been tested by several numerical problems of shell structures. Numerical results indicate that this shell element shows fast convergence and reliable solutions.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.1
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• pp.69-76
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• 2003

Low-tension cables have been increasingly used in recent years due to deep-sea developments and the advent of synthetic cables. In the case of low-tension cables, large displacements may happen due to relatively small restoring forces of tension and thus the effects of fluid and geometric non-linearities and bending stiffness. A Fortran program is developed by employing a finite difference method. In the algorithm, an implicit time integration and Newton-Raphson iteration are adopted. For the calculation of huge size of matrices, block tri-diagonal matrix method is applied, which is much faster than the well-known Gauss-Jordan method in two point boundary value problems. Some case studies are carried out and the results of numerical simulations are compared with a in-house program of WHOI Cable with good agreements.

• 한국지구물리탐사학회:학술대회논문집
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• 2001.09a
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• pp.57-74
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• 2001

The risk of the soil and groundwater that contaminated with petroleum is well known. The behaviour of petroleum in subsurface is governed by combined mechanism of several processes such as volatilization, adsorption, dissolution, biodegradation, etc. Large number of methods of remedial investigation and plan, therefore, have been developed and practiced. In application of the method, it is required engineer understands the mechanism of fate of petroleum in subsurface. So sampling procedures is very important for investigating the type of contaminants and their concentration as well as the selection of items that must be tested. For designing the remedial method, it is also required engineers to verify the structural formation of geology and the locational conditions of a land in detail, to familiar with the regulation, and to investigate the problems that can be happened after the performance was begun. In this paper it is shown that the investigation methods of contaminated land and the proper selection procedure of remedial method using the case history.

• Proceedings of the Botanical Society of Korea Conference
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• 1987.07a
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• pp.191-211
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• 1987

Common usage of the concept of juvenility implies that there is one physiological phase, the juvenile phase, which manifests itself in the various morphological and physiological phenomena observed in juvenile higher plants. The juvenile phase is often defined as that time from seed germination until the plant attains the ability to flower regulating such behaviour. This definition precludes plants from flowering in the juvenile phase. It is of major interest, therefore, to identify the physiological controls(Bluehreife) regulating such behavior. The length of the juvenile period in higher plants ranges from one year to over 60 years in different species. The long juvenile period of seedling is the main cause of the long duration of the breeding process. I determined the length of the juvenile period in various plants and its control of phase changes in natural system in relation to factors such as plant size and age, shoot morphology, apex size, root system and phytohormonal and nutritional status is reviewed. From the own experimental and observational evidence available it appears that both hormonal and nutritional factors can be involved in control of juvenility but that a specific juvenile or flowering hormone is not involved. Grafting, ringing, scoring, root pruning and fertilization have been used to accelerate flowering, but in most cases these cultured treatments are only successful on plants that were passed the juvenile phase. It is suggested that there are intrinsic difference between the meristematic cells of the apieces of juvenile and adult shoot, which are thus determined with respect to there development potentialities. The problems associated with the maintenance of the determined state through mitosis are discussed. The properties of transitional forms of Ribes nigrum L. intermediate between the juvenile and adult phase, are descrived and there implications discussed. Analogies are drawn between juvenile phenomena in woody perennials and in herbaceous species.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.3
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• pp.482-488
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• 2009

Mobile Ad-hoc Networks provide communication without a centralized infrastructure, which makes them suitable for communication in disaster areas or when quick deployment is needed. On the other hand, they are susceptible to malicious exploitation and have to face different challenges at different layers due to its open Ad-hoc network structure which lacks previous security measures. Denial of service (DoS) attack is one that interferes with the radio transmission channel causing a jamming attack. In this kind of attack, an attacker emits a signal that interrupts the energy of the packets causing many errors in the packet currently being transmitted. In harsh environments where there is constant traffic, a jamming attack causes serious problems; therefore measures to prevent these types of attacks are required. The objective of this paper is to carry out the simulation of the jamming attack on the nodes and determine the DoS attacks in OPNET so as to obtain better results. We have used effective anomaly detection system to detect the malicious behaviour of the jammer node and analyzed the results that deny channel access by jamming in the mobile Ad-hoc networks.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1997.11a
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• pp.44-48
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• 1997

The Swedish Fire Research Board was established in 1979 to initiate and fund relevant fire research efforts. The Board is responsible for a long term research programme revised every third year, and the Board is one of two major Swedish sponsors of all fire research. Beside the Board we also have the Swedish National Rescue Services, funded by the government. BRANDFORSK gives very high priority for the industry and the insurance company and the need they express for fire research. Research that the Rescue Services Board are funding is mainly focusing the need for the fire department. The Swedish Fire Research Board, BRANDFORSK, is the joint agency of the Swedish government, the insurance industry and the business sector, for the initiation, funding and supervision of different kinds of fire research. Work is directed by a Programme Board and is performed in the form of projects at universities, research institutes, state authorities and private firms. The Secretariat of BRANDFORSK shares the premises of the Swedish Fire Protection Association, SFPA, and the SFPA is the principal and the party which enters into agreement with the State. The programme for the period 1997-1999 has been drawn up on the basis of both damage development and the trends in society which can be noted, and the evident fire problems of the interested parties and their need for fire research. The inputs in the programme have been broken down seven problem areas. In every problem area different project areas are set out, and these primarily specify the aim of the work. Our seven problem-areas are; Costs and benefits of fire protection measure. The role and behaviour of people and organizations Fire In buildings Fire in underground facilities Rescue operations fire in industries Fire and the environment. In comparison with previous fire research programmes, cost/benefit studies have been accorded higher priority, and this is also reflected in other problem areas. Grater Emphasis

• Explosives and Blasting
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• v.37 no.2
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• pp.14-21
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• 2019

Distinct element method is a powerful numerical tool for modelling the jointed rock masses. It is also a useful tool for modelling of later stage of blasting requiring large displacement. The distinct element method utilizes a rigid block idea in which the interacting force between distinct elements is calculated from contact displacement as elements penetrate slightly. The properties of joints defined as the boundaries of distinct elements are critical parameters to determine the block behavior, and affect the deformation and failure mode. However, regardless of real joint properties, joint stiffnesses have sometimes been selected without special concern just to prevent elements from penetrating too far into each other in some quasi-static problems. Depending on whether the main interest in the analysis is the prediction of the deformation with high precision, or the prediction of the block behaviour after failure, the input data such as joint stiffness may or may not have a significant effect on the results. The purpose of this study is to provide a sound understanding of the effect of the joint stiffness on the distinct element analysis results, and to help guide the selection of input data.