• Analytical Science and Technology
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• v.16 no.5
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• pp.1041-1051
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• 2003

Neutron induced prompt gamma activation analysis (PGAA) offers a nondestructive, sensitive and relatively rapid method for the determination of trace and major elements and is proven to be convenient for online analysis of minerals, metals, coal, cement, petrochemical, coating, paper as well as many other materials and products. The technique has found many uses in medicine, industry, research, security and the detection of contraband items. This report reviews the present status and future trends of the PGAA techniques. Requirements for the system are neutron source, high resolution HPGe detectors with a high-voltage power supply, an amplifier, analog-to-digital converter, and a multichannel analyzer for the detection and measurement of prompt ${\gamma}$-ray emit form the neutron capture elements. Introducing a ${\gamma}$-${\gamma}$ coincidence system also improves the quality of the ${\gamma}$-ray spectrum by suppressing the background created from the Compton scattering of high energy prompt ${\gamma}$-rays. A PGAA system using a $^{252}Cf$ neutron source is currently under construction for the on-line measurement of several elements in aqueous samples at KAERI. The system can be applied for the detection of chemical weapons and explosives as well as various narcotics.

• Journal of Conservation Science
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• v.33 no.5
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• pp.355-362
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• 2017

The Nongso tomb of Sunchang was built in a relatively deep place; hence there was little damage from grave robbers. The tomb was completely filled with a large amount of charcoal, and therefore the wooden coffin was excavated in relatively good condition. On the basis of the structure of the tombs, excavated artifacts, and radiocarbon dating results, the tomb is estimated to be from between the late Goryeo and the early Joseon period. The wooden coffin excavated is double-layered structures consisting of an outer coffin and an inner coffin. The outside of the wooden coffin is thickly lacquered and decorated with yellow letters and white motifs. An analysis of the pigments' components revealed that the major component of the letters was gold (Au) and the major component of the motifs was silver (Ag). The coffin lacquer had three layers: a pigment layer, a yellowish-brown layer, and a black layer. The wooden bases of the coffins were painted with a black substance, such as soot, as mineral elements were not detected in the black layer. The yellowish-brown layer is presumed to be refined lacquer. From the analysis of the structure of the layers and pigments, we can estimate the method was adopted for making lacquer for wooden coffin. It is assumed that the method used gold leaf and gold powder. The form of the pigment and the internal structure are likely to be gold leaf, but the shape of the surface letters appears to have been formed using gold powder. This study will serve as important information for understanding lacquer making techniques at the time of the tombs' construction by confirming the making method through reproduction experiments using gold leaf and gold powder.

• Explosives and Blasting
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• v.17 no.4
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• pp.67-88
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• 1999

Ground settlements induced by tunnel excavation cause the foundations of the neighboring superstructures to deform. An expert system called NESASS was developed to analyze the structural safety of such superstructures. NESASS predicts the trend of ground settlements to be resulted from tunnel excavation and carries out a safety analysis for superstructures on the basis of the predicted ground settlements. Using neural network techniques, NESASS learns a data base consisting of the measured ground settlements collected from numerous actual fields and infers a settlement trend at the field of interest. NESASS calculates the magnitudes of angular distortion, deflection ratio, and differential settlement of the structure and, in turn, determines the safety of the structure. In addition, NESASS predicts the patterns of cracks to be formed on the structure using Dulacskas model for crack evaluation. In this study, the ground settlements measured from the Seoul subway construction sites were collected and sorted with respect to the major factors influencing ground settlement. Subsequently, a database of ground settlement due to tunnel excavation was built. A parametric study was performed to verify the reliability of the proposed neural network structure. A comparison of the ground settlement trends predicted by NESASS with the measured ones indicates that NESASS leads to reasonable predictions. An examples is presented in this paper where NESASS is used to evaluate the safety of a structure subject to deformation due to tunnel excavation near to the structure.

• Geophysics and Geophysical Exploration
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• v.20 no.2
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• pp.100-113
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• 2017

Induced polarization (IP) method is based on the measurement of a polarization effect known as overvoltage of the ground. IP techniques have been usually used to find mineral deposits, however, nowadays widely applied to hydrogeological investigations, surveys of groundwater pollution and foundation studies on construction sites. IP surveys can be classified by its source type, i.e., time-domain IP estimating chargeability, frequency-domain IP measuring frequency effect (FE), and complex resistivity (CR) and spectral IP (SIP) measuring complex resistivity. Recently, electromagnetic-based IP has been studied to avoid the requirement for spike electrodes to be placed in the ground. In order to understand IP methods in this study, we: 1) classify IP surveys by source type and measured data and illustrate their basic theories, 2) describe historical development of each IP forward modeling and inversion algorithm, and finally 3) introduce various case studies of IP measurements.

• Journal of the Korean Society of Hazard Mitigation
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• v.3 no.2 s.9
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• pp.99-110
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• 2003

In this study, lightening material weight and normalizing structure of preventing system of landslide soil-rock in trench excavation was tried with focusing in safety construction availability and workability. In other words, risk estimate, safety management method investigation, applicability of bracing material and mechanical stability of bracing structure was studied. From these result, structural stability and structural analysis of light weight bracing structure was carried out with common structural analysis program, for examining movement mechanism of bracing structure and normalization of standard. The result are summarized as following. (1) Mechanical ability of bracing members and soil pressure parameter acting to member for ensuring mechanical propriety of bracing structural and useful of new material considering soil mechanics boundary were proposed. Also theory and method of analysis of bracing structural were proposed. (2) As a result of the structure analysis of geographical profile for light pannel used FRP as hard clay mechanical characteristics(bending moment, shear force, axial force) of panel were changed according to groundwater level and it is proved that the result of mechanical analysis is within allowable stress. Thus, light pannel is available for bracing structure in trench excavation.

• The Journal of the Korea Contents Association
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• v.6 no.9
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• pp.98-107
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• 2006

By improving performance of mobile machine(3D engine, 3D accelerator chip set, etc) and developing wireless network technology, a demand for actual contents of users is being increased rapidly. But, there are some difficulties yet for the speedy development of actual contents because of the limitation of development resources that is dependent on each mobile device's different performance. In general, much of the animated character-creation work for mobile environment is still done manually by experienced animator with the method of key frame processing. However, it needs a lot of time and more costs for creating motion. Additionally, it is possible to cause a distortion of motion. In this paper, I solved the difficulties by using a optical motion capture system, it was able to acquire accurate motion data more easily and quickly, and then it was possible to make 3D dance contents efficiently. Also, I showed techniques of key reduction and controlling frame number for using huge amounts of motion capture data in mobile environment which requires less resources. In making 3D dance contents, using an optical motion capture system was verified that it was more efficient to make and use actual-reality contents by creating actual character motion and by decreasing processing time than existing method.

• Journal of Distribution Science
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• v.10 no.5
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• pp.29-36
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• 2012

This paper aims to establish a Fengshui-based marketing model that companies engaged in selling dwelling spaces can utilize to increase their sales. The study is based on an investigation of appraisal statements and analysis techniques used in Fengshui. The Fengshui marketing model can be used for corporate advertising, sales promotions, public relations events, and for framing an overall marketing strategy according to changing consumer demand. As a sales promotion strategy, it can be used to influence consumer psychology and behavior. Although this study is limited to the all-pervasive advertising and marketing of houses by construction companies under installment plans, the Fengshui marketing method can also be used for the sale of store locations, space for product display, and so on. Initially, I analyze living spaces according to traditional Fengshui theory, and subsequently apply the modern method to study topographical space structures and geomagnetism disturbances. I present a standard form for writing the Fengshui appraisal statement based on the objective analytical method of Fengshui. With its shortcomings remedied, the appraisal statement can lead to high-quality advertising and increased valuations because it is based on objective data analysis and systematic evaluation of houses. In brief, I have designed the Fengshui marketing model as a sales promotion technique for the housing industry. I believe this study will contribute to the application of Fengshui in the housing industry's sales promotion efforts through high-quality advertising. Future research should evaluate Fengshui marketing in the housing industry based on case studies. Research questions to be addressed could include how Fengshui marketing has affected installment sales of houses and how Fengshui architectural practices affect general well-being. These studies would help propagate Fengshui marketing by validating its effectiveness. In addition, case studies should be undertaken to consider the practical applications of Fengshui marketing, how it can contribute to maximizing a company's image and profits, and how it can promote customer satisfaction.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.6
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• pp.713-719
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• 2001

The aim of this study is to check the application criteria of the conventional techniques and clarify the effects of breaker depth, seabed conditions on the stability in relation to the effects of uncertainty of storm duration and directional irregular waves. The typical damage modes were divided by the direct wave force on the armor unit and by the local scouring around the toe of a breakwater head by the model experiments. The destruction modes are defined, and some criteria on the damage modes and scouring/deposition at the toe of a breakwater head in relating the wave-bottom-structural conditions can be checked using the multi-directonal irregular wave generator system. According to the results, it is emphasized that the 3-D effects on the stability should be analyzed in the design of multi-purpose/function coastal structures in consideration of the evaluation of spatial variation of damage modes and hydraulic characteristics as well as the wave distribution along the structures.

• Journal of Convergence for Information Technology
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• v.10 no.11
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• pp.55-63
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• 2020

The IoT technology is a field that applies and converges the technologies in the existing industrial environment, instead of new technologies. The IoT technology is releasing various application services converged with other industries such as smart home, healthcare, construction, and automobile, and it is also possible to secure the work efficiency and convenience of users of IoT-based technologies. However, the security threats occurring in the IoT-based technology environment are succeeding to the vulnerability of the existing wireless network environment. And the occurrence of new and variant attacks in the combination with the ICT convergence environment, is causing damages. Thus, in the IoT technology-based environment, it would be necessary to have researches on the safe transmission of messages in the communication environment between user and device, and device and device. This thesis aims to design a safe communication protocol in the IoT-based technology environment. Regarding the suggested communication protocol, this thesis performed the safety analysis on the attack techniques occurring in the IoT technology-based environment. And through the performance evaluation of the existing PKI-based certificate issuance system and the suggested communication protocol, this thesis verified the high efficiency(about 23%) of communication procedure. Also, this thesis verified the reduced figure(about 65%) of the issued quantity of certificate compared to the existing issuance system and the certificate management technique.

• Journal of Ship and Ocean Technology
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• v.5 no.3
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• pp.1-13
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• 2001

Present-day rules and regulations for the design and construction of ships are almost without exemption of a prescriptive and deterministic nature. Often it is argued that this situation is far from ideal; it does no right to the advances, which have been made during the past decades in engineering tools in marine technology, both in methodology and in computational power. Within IMO this has been realized for some time and has resulted in proposals to use Formal Safety Assessment(FSA) as a tool to improve and to modernize the rule making process. The present paper makes use of elements of the FSA methodology, but instead of working towards generic regulations or requirements, a Risk Assessment Approach, not unlike a 'safety case'; valid for a certain ship or type of ship is worked out. Delft University of Technology investigated the application of safely assessment procedures in ship design, in co-operation with Anthony Veder Shipowners and safety experts from Safely Service Center BV. The ship considered is a semi-pressurized-fully refrigerated LPG carrier. On the basis of the assumption that a major accident occurs, various accident, scenarios were considered and assessed, which would impair the safety of the carrier. In a so-called Risk Matrix, in which accident frequencies versus the consequence of the scenarios are depicted, the calculated risks all appeared lo be in the ALARP('as low as reasonable practicable') region. A number of design alternatives were compared, both on safety merits and cost-effectiveness. The experience gained with this scenario-based approach will be used to establish a set of general requirements for safety assessment techniques in ship design. In the view that assessment results will be most probably presented in a quasi-quantified manner, the requirements are concerned with uniformity of both the safety assessment. These requirements make it possible that valid comparison between various assessment studies can be made. Safety assessment, founded on these requirements, provides a validated and helpful source of data during the coming years, and provides naval architects and engineers with tools experience and data for safety assessment procedures in ship design. However a lot of effort has to be spent in order to make the methods applicable in day-to-day practice.