• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.1966-1973
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• 2023

Virtual reality technology has been widely used in the field of nuclear and radiation safety, dose rate computing in virtual environment is essential for optimizing radiation protection and planning the work in radioactive-controlled area. Because the CPU-based gamma dose rate computing takes up a large amount of time and computing power for voxelization of volumetric radioactive source, it is inefficient and limited in its applied scope. This study is to develop an efficient gamma dose rate computing code and apply into fast virtual simulation. To improve the computing efficiency of the point kernel algorithm in the reference (Li et al., 2020), we design a GPU-based computing framework for taking full advantage of computing power of virtual engine, propose a novel voxelization algorithm of volumetric radioactive source. According to the framework, we develop the GPPK(GPU-based point kernel gamma dose rate computing) code using GPU programming, to realize the fast dose rate computing in virtual world. The test results show that the GPPK code is play and plug for different scenarios of virtual simulation, has a better performance than CPU-based gamma dose rate computing code, especially on the voxelization of three-dimensional (3D) model. The accuracy of dose rates from the proposed method is in the acceptable range.

• Journal of the Korea Safety Management & Science
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• v.5 no.3
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• pp.107-119
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• 2003

Expectation and interest about e-CRM are rising for more efficient customer management in on-line including electronic commerce. The decision-making tree can be used usefully as the data mining technology for e-CRM. In this paper, the representative decision making techniques, CART, C4.5, CHAID analyzed the differences in personalization point of view with actuality customer data through an experiment. With these analysis data, it is proposed a new decision-making tree system that has big advantage in personalization techniques. Through new system, it can get following advantage. First, it can form superior model more qualitatively in personalization by adding individual's weight value. Second it can supply information personalized more to customer. Third, it can have high position about customer's loyalty than other site of similar types of business. Fourth, it can reduce expense that cost marketing and decision-making. Fifth, it becomes possible that know that customer through smooth communication with customer who use personalized service wants and make from goods or service's quality to more worth thing.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.696-703
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• 2015

This paper is a follow-up research of 'A study on the development of Safety Management Evaluation Index for Shipping Company'. It aims to develop the evaluation items of Safety Management Index(hereafter called as 'SMI') applicable to 'Safety Advantage Point', which is suggested as the sub-index of 'Safety Management Evaluation Index' function in the preceding research and also verify their adequacy. For that purpose, firstly, the 11 evaluation items were developed after collecting the practical opinions from safety management personnels in Korean shipping companies. Secondly, the survey was carried out for the verification of the adequacy of the 11 evaluation items. And lastly, its results was analysed, whether it has statistical meanings of differences in adequacy awareness amongst safety managers grouped depending on business type(coastal, ocean-going) and business capacity(number of owned-operating ships). As a result, there was no relevance between their adequacy awareness and business type of their companies. However, a difference in their adequacy awareness existed depending on their companies' business capacity(small, medium and large sized). In conclusion, when the safety management level of shipping companies is evaluated by SMI, the same indices can be applicable to both coastal and ocean-going shipping companies by a grouping of companies' business capacity.

• Journal of the Korean Society of Safety
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• v.27 no.5
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• pp.105-110
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• 2012

Steel elements are widely used for temporary structures on every construction site. but despite its strong resistences against heavy concrete volumes, they are easily eroded by oxygens in the space as times have been gone. If they are used several times in the construction fields, their elements are rusted and deformed and the strength is gradually reduced through the weak part. From this point of view, aluminum pipe support has been developed in stead of steel pipe sopport with enhancing durability against oxygens all the more. The developed aluminium pipe support has been lighter than steel unit, so workability has been improved. In another advantage of aluminium pipe support, different level control is possible with being equipped with the level control nut which enables the length adjustment of aluminium pipe support and the collapse of aluminum pipe support could be also prevented from the structures in the long term.

• Journal of Auto-vehicle Safety Association
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• v.11 no.2
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• pp.29-34
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• 2019

This paper presents a new method for construction of a static obstacle map. A static obstacle is important since it is utilized to path planning and decision. Several established approaches generate static obstacle map by grid method and counting algorithm. However, these approaches are occasionally ineffective since the density of LiDAR layer is low. Our approach solved this problem by applying probability theory. First, we converted all LiDAR point to Gaussian distribution to considers an uncertainty of LiDAR point. This Gaussian distribution represents likelihood of obstacle. Second, we modeled dynamic transition of a static obstacle map by adopting the Hidden Markov Model. Due to the dynamic characteristics of the vehicle in relation to the conditions of the next stage only, a more accurate map of the obstacles can be obtained using the Hidden Markov Model. Experimental data obtained from test driving demonstrates that our approach is suitable for mapping static obstacles. In addition, this result shows that our algorithm has an advantage in estimating not only static obstacles but also dynamic characteristics of moving target such as driving vehicles.

• Nuclear Engineering and Technology
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• v.44 no.2
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• pp.113-150
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• 2012

The point we made in this paper is that, although detailed and precise three-dimensional (3D) whole-core transport calculations may be obtained in the future with massively parallel computers, they would have an application to only some of the problems of the nuclear industry, more precisely those regarding multiphysics or for methodology validation or nuclear safety calculations. On the other hand, typical design reactor cycle calculations comprising many one-point core calculations can have very strict constraints in computing time and will not directly benefit from the advances in computations in large scale computers. Consequently, in this paper we review some of the deterministic 3D transport methods which in the very near future may have potential for industrial applications and, even with low-order approximations such as a low resolution in energy, might represent an advantage as compared with present industrial methodology, for which one of the main approximations is due to power reconstruction. These methods comprise the response-matrix method and methods based on the two-dimensional (2D) method of characteristics, such as the fusion method.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.2
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• pp.417-423
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• 2012

In this paper, In order to make up for the weak point of driving structure that existing used single motor in motor design, as a method to make use of advantage for joint of hollow type, we propose implementation methods for high torque, high precision, backlash less, and design of secondary safety device, and application method through joint organization using multiple motors.

• Journal of the Korea Safety Management & Science
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• v.15 no.1
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• pp.141-150
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• 2013

In this paper, the learnability of haptic icons was tested as a way of conveying turn-by-turn directions to users involved in navigation interactions with commercial smartphones. To do this, six most distinctive haptic icons were identified from those having different duration of each pulse, interval between pulses, and rhythm. Associations between the selected haptic icons and 3 pairs of navigation directions were analyzed using data gathered from 30 subjects by 7 point Likert scale. The haptic icons were then assigned to proper directions based on the results from that stereotype analysis. The results showed that the commercial smartphone with one linear motor at a fixed location is not capable of making hapticons to have clear directional stereotypes. The hapticons with poor stereotypes has no advantage in learnability compared to those of random assignment.

• Journal of Ocean Engineering and Technology
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• v.27 no.6
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• pp.22-26
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• 2013

The purpose of this study was to improve the design of a mooring line by attaching a lumped mass to it on the seabed. A numerical analysis of the redesigned mooring system is performed to analyze the effect of the weight of the attached lumped mass using the commercial software Orcaflex. The ultimate tension of the mooring system with the lumped mass is compared with that of a bare mooring line in the original design. An appropriately designed weight for the lumped mass is found to induce a critical lifted point in the mooring line by floater motion in the ultimate condition to move toward the floater position from the anchor point, while maintaining a similar safety factor for the mooring line. On the other hand, it is shown that excess weight for the lumped mass induces snapping in a mooring line, resulting in low safety factor for the mooring system. The distance between lumped weights is shown to be a minor parameter affecting the safety of a mooring line, although a shorter line has an advantage from an economic point of view. Using the optimal weight for the lumped mass attached to the mooring line on a seabed reduces the mooring line length and installation area occupied by a mooring system under real sea conditions.

• Journal of the Optical Society of Korea
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• v.18 no.5
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• pp.523-530
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• 2014

Machine material and structural strain are critical factors for appraising mechanical properties and safety. Particularly in three and four-point bending tests, which appraise the deflection and flexural strain of an object due to external force, measurements are made by the crosshead movement or deflection meter of a universal testing machine. The Digital Image Correlation (DIC) method is one of the non-contact measurement methods. It uses the image analyzing method that compares the reference image with the deformed image for measuring the displacement and strain of the objects caused by external force. Accordingly, the advantage of this method is that the object's surface roughness, shape, and temperature have little influence. However, its disadvantage is that it requires extensive time to compare the reference image with the deformed image for measuring the displacement and strain. In this study, an algorithm is developed for DIC that can improve the speed of image analysis for measuring the deflection and strain of an object caused by a three-point bending load. To implement this algorithm for improving the speed of image analysis, LabVIEW 2010 was used. Furthermore, to evaluate the accuracy of the developed fast correlation algorithm, the deflection of an aluminum specimen under a three-point bending load was measured by using the universal test machine and DIC measurement system.