• The Journal of the Acoustical Society of Korea
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• v.36 no.1
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• pp.1-11
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• 2017

In this study, novel approximate form of the square-root operator of three dimensional acoustic Parabolic Equation (3D PE) is proposed using a rational approximant for two variables. This form has two advantages in comparison with existing approximation studies of the square-root operator. One is the wide-angle capability. The proposed form has wider angle accuracy to the inclination angle of ${\pm}62^{\circ}$ from the range axis of 3D PE at the bearing angle of $45^{\circ}$, which is approximately three times the angle limit of the existing 3D PE algorithm. Another is that the denominator of our approximate form can be expressed into the product of one-dimensional operators for depth and cross-range. Such a splitting form is very preferable in the numerical analysis in that the 3D PE can be easily transformed into the tridiagonal matrix equation. To confirm the capability of the proposed approximate form, comparative study of other approximation methods is conducted based on the phase error analysis, and the proposed method shows best performance.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.71-72
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• 2022

In the case of free-form buildings, it is difficult to reuse the form for panel production because the shape and size of the interior and exterior panels of the building are different. In general, it is a free-form concrete panel (FCP) production technology using the existing plywood formwork, and the form is produced in a different shape each time and is discarded after only one use. The production of these disposable forms requires enormous resources, including materials, labor and time. Hence, it is necessary to develop innovative forms that can be reused for sustainable FCP construction. In this study, a technology has been developed that combines 3D Plastering Technique (3DPT) to produce FCP. By applying this technology to free-form building projects, the time and cost required for FCP production can be reduced. However, specific studies on the production process for this technology have not been done yet. Therefore, the objective of this study is a basic study of free-form concrete panel production process using 3D plastering technique.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.7
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• pp.965-971
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• 2017

The primary objective of this study was to assess the energy efficiency performance of an optimized hull form capable of saving energy based on existing vessels. The bow shape of existing vessels was investigated, giving consideration to design draft and speed. Resistance performances were also assessed for existing vessels according to operating conditions. Commercial CFD codes and model test materials were used to assess effective power. An optimized hull form with minimum resistance was selected given real operating conditions. The effective horsepower of existing and optimized vessels was estimated at three speeds. Resistance performance for an optimized vessel showed a 6 % improvement in effective horsepower at design speed (12 knots) compared to existing vessels. Quasi-propulsive efficiency employed experimental data, while energy efficiency performance was analyzed based on operating days, bunker fuel oil C cost, daily fuel oil consumption and specific fuel oil consumption. Energy efficiency performance for an optimized vessel showed a gain of 30 million won per year in reduced costs at design speed (12 knots) compared to existing vessels.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.46
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• pp.29-60
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• 2010

The incentive and reasons to publish FIDIC Conditions of Contract for Design, Build and Operate Projects(DBO Form) are manifold. It is partly a response to the increasing need for sophisticated project delivery methods in both the public and private sectors and the already widespread use of the FIDIC Yellow Book with operation and maintenance obligations and partly a response to the challenge to decrease maintenance cost to a minimum by means of a new procurement route. As a result, FIDIC has developed a new model form to meet this market place requirement. On the other hand, FIDIC did not simply adapt the Yellow Book but has developed a new form from it, whilst preserving the style of the already known FIDIC Forms and maintaining the wording where it was not necessary to change it for the purposes of a DBO Form. Moreover DBO Form fills up supposed gaps in other FIDIC Forms and ameliorates the claim management and dispute management framework. FIDIC DBO approach may be shortly summarized as follows. First, DBO Form provides for single project responsibility. Second, DBO Form has the clear objective of ensuring the use of a most reliable and efficient technology at the lowest life-cycle cost. Third, DBO Form is intended to operate as an effective quality increase in the design and construction of projects. Fourth, DBO Form is intended to provide significant benefits with regard to system integration and reduction of risks. Fifth, DBO Form accelerates and enhances completion schedule compliance. Sixth, DBO takes care of all three supporting pillars of sustainability(including economical, environmental and social elements). DBO Form is obviously a good starting point for negotiations and the preparation of calls for tenders, thus saving the parties time and money. However, existing cultural and legal differences, particular local conditions and the particular needs of some branches of the industry may require the form to be adapted according to the particular needs of a project. And Civil law practitioners are strongly recommended to verify carefully the underlying legal concepts and background of each clause of the General Conditions in order to avoid unnecessary and sometimes unnatural changes and amendments being made. Note that when preparing the Particular Conditions ensure that terminology is consistent and that existing inherent concepts should not be ignored.

• Korean Institute of Interior Design Journal
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• v.23 no.5
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• pp.3-13
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• 2014

Typology in Contemporary Architecture wants to escape from the classical typology that has the problems about specific program of structuralism, typical repeatation of customary form. As visible and non-visible things are appeared in contemporary architecture through the analysis of the inner system involving development process of changing itself, typology of contemporary is utilized at a tool of form generation in the process of architect. And it notes that the structural properties of the building system. The form of contemporary architecture has the new connecting strucure not reduced to existing ones. It carries out generative access as a device in order to solve the complexity of society. From this perspective, we analyze the process of projects of contemporary architects that can be typological strategy not representation of post geometric form but a tool of form generation in architectural process. As a result, we can find four characteristics of typology as a tool of form generation; 'interference and mix of program', 'continous slabs', 'rearrangement through relationship setting', 'transformation of multi-layers'. These are expanding to the process that reflect history and context or infer from morphology. Therefore, typology as architectural process of form generation overcomes morphological typology of classical typology and suggests that the different architectural approach having potential possibility.

• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.3_4
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• pp.82-89
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• 1995

The efforts of formulation have been reviewed and the results of existing laboratory experiments are investigated in order to describe the contracted flow which occurs at the final closure of sea dike construction. The regional characteristics of contracted flow is analyzed by checking the drawdown curve, and Chezy's mean velocity equation is employed to estimate the discharge rate at the closure. Weir-type discharge equations are reviewed, which are derived from Bernoulli equation, and the problems of the equations are discussed. Chezy's mean velocity equation is considered to be widely and generally applicable, and the empirical factor introduced in Chezy's equation is named 'form drag factor' since it is primarily dependent on the form drag caused by the contraction of discharge area. Laboratory experiments were conducted mainly in order to investigate the variation of form drag factor against various parameters, and an empirical equation is developed for the estimation of form drag factor.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.6-7
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• 2021

Although the development of free-form architectural technology continues, it consumes a lot of money and time due to the one-time formwork and the difficulty of maintaining quality due to manual work. To this end, in this study, a shape connection technique was proposed and verified to improve the limitations of implementing the curved surface of the existing lower multi-point press. In order to improve the accuracy of the shape, a curved surface was implemented using a silicon cap and a silicon plate. As a result of the error analysis of the shape, a small value of less than 3 mm was found. This study can implement more accurate curved surfaces than conventional technologies and produce high-quality free-form panels.

• Journal of Korean Institute of Industrial Engineers
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• v.21 no.3
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• pp.441-461
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• 1995

This research proposes an Integrated Product Information Model (IPIM) using STEP (Standard for the Exchange of product model data) for Computer Integrated Manufacturing (CIM) of Concurrent Engineering (CE). IPIM is based on Geometry and Topology (STEP Part 42), Form Feature (STEP Part 48), and Tolerance (STEP Part 48) for representing the integrated information of mechanical parts. For the IPIM, 1) new entities are developed for integration of existing entities, and 2) the existing entities are restructured and modified for a special application protocol. In CIM or CE, the advantages of using IPIM having integrated form of geometry, feature and tolerance are 1) integration of product design, process design and manufacturing sequentially or concurrently. 2) keep the product data consistency, modified by different domain, and 3) automatic data exchange between different application software and different hardware. The prototype system is composed of CAD, Data Probe, DBMS and SDAI (Standard Data Access Interface), and the generated STEP data is stored in a step file of DBMS for other applications.

• The Korean Journal of Pain
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• v.27 no.1
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• pp.16-22
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• 2014

Psychosomatic disorders are defined as disorders characterized by physiological changes that originate partially from emotional factors. This article aims to discuss the psychosomatic disorders of the oral cavity with a revised working type classification. The author has added one more subset to the existing classification, i.e., disorders caused by altered perception of dentofacial form and function, which include body dysmorphic disorder. The author has also inserted delusional halitosis under the miscellaneous disorders classification of psychosomatic disorders and revised the already existing classification proposed for the psychosomatic disorders pertaining to dental practice. After the inclusion of the subset (disorders caused by altered perception of dentofacial form and function), the terminology "psychosomatic disorders of the oral cavity" is modified to "psychosomatic disorders pertaining to dental practice".

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.5_6
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• pp.213-222
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• 2003

Most existing algorithms adopt the forward mapping method that is based on vector representation. Problem of existing algorithms Is the exponential increase of memory usage with number of layers. This degrades the accuracy of the boundary pattern representation. Our method uses bitmap representation and does not require any additional post-processing for conversion of vector-form results to bitmap-form. A new and efficient algorithm is presented in this paper for the generation of hyperbolic patterns by means of backward mapping methods.