• Journal of the Korean Society for Nondestructive Testing
• /
• v.14 no.4
• /
• pp.228-236
• /
• 1995

In this paper the method to evaluate shielding deficiency by gamma scanning test was presented and verified theoretically by Monte Carlo code which is one of the best effective method for radiation shielding calculation. The cylindrical shielding model was selected to evaluate shielding deficiency by gamma scanning test. First, the reference shielding according to the design requirement of cask was fabricated specially and reference values were measured with Co-60 source and scintillation detector. As a result with which calculated the reference values, it is shown that maximum deficiency thickness for lead of true cylindrical shielding model was 12mm. To verify this, thickness of lead was calculated by MCNP code and maximum deficiency thickness was 11.6mm. The experimental result obtained by the use of reference shielding was in good agreement with the theoretical result within 4.1%. So, this method can be applied to inspect the shielding ability for great shielding or cask which the radioactive material is used. To perform measurement more exactly, the further work on the development of measuring equipment to display the results on the screen will be required.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• v.16 no.1
• /
• pp.31-49
• /
• 2012

In this paper, we propose a very efficient method which reconstructs the high resolution surface from a set of unorganized points. Our method is based on the level set method using adaptive octree. We start with the surface reconstruction model proposed in [20]. In [20], they introduced a very fast and efficient method which is different from the previous methods using the level set method. Most existing methods[21, 22] employed the time evolving process from an initial surface to point cloud. But in [20], they considered the surface reconstruction process as an elliptic problem in the narrow band including point cloud. So they could obtain very speedy method because they didn't have to limit the time evolution step by the finite speed of propagation. However, they implemented that model just on the uniform grid. So they still have the weakness that it needs so much memories because of being fulfilled only on the uniform grid. Their algorithm basically solves a large linear system of which size is the same as the number of the grid in a narrow band. Besides, it is not easy to make the width of band narrow enough since the decision of band width depends on the distribution of point data. After all, as far as it is implemented on the uniform grid, it is almost impossible to generate the surface on the high resolution because the memory requirement increases geometrically. We resolve it by adapting octree data structure[12, 11] to our problem and by introducing a new redistancing algorithm which is different from the existing one[19].

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.34 no.3
• /
• pp.74-80
• /
• 2006

This paper deals with the control and fault monitoring of a DDV hydraulic actuation system. A hydraulic servo system has a nonlinear dynamics of an orifice flow through a valve spool. A full nonlinear model for a DDV actuation system is driven, and linearized to a simple model which is convenient for a control loop and fault monitor design. A top level requirement on the performance and safety for the actuation system is introduced. A control system and fault monitoring structure which can meet these requirements are discussed. A simulation package for a DDV actuation system which has a triplex redundant structure is developed.

• Archives of design research
• /
• v.15 no.1
• /
• pp.37-48
• /
• 2002

In the face of rapidly changing society and consumer cognition, eyer-increasing importance of strategies for creating good images for a company among critical factors inf1uencing management in terms of its survive is prevalent. Today, many companies strive for getting or improving their images with advertisements for corporate identity as well as public advertisements, which is considered as a requirement of this society and age for good images of companies rather for only good products and services. In this study, we analyzed and compared the largest companies in Korea, mainly in their printed materials for advertisements over the last 10 years from 1990. Corporate advertisements performed by domestic companies could be classified into several types based on their theoretical backgrounds and creative concepts. Basic theoretical backgrounds of corporate advertisements induced in the study are recognitive-psychological model and associative learning model. And, six areas of cases were classified and analysed in terms of their such creative concepts as random difference, competitive advantage and specific creativity. We analyzed and compared cases of strategies for domestic corporate advertisements with reference to these six each area in their effects and problems in terms of theoretical and practical aspects and thereby purpose to provide companies with reference in developing strategies for corporate advertisements of companies.

• Journal of Energy Engineering
• /
• v.10 no.3
• /
• pp.233-242
• /
• 2001

This paper attempts to analyze the effects of promotion of natural gas vehicles (NGVs) on LNG storage facilities and load patterns, and to verify economic feasibilities of NGVs as a DSM (Demand-Side Management) strategy. For these purpose, we have established an econometric mode. Results from the model indicate that natural gas demand in transportation sector will increase continuously, having a 7.84% share in total natural gas demand in 2014. By this analysis, the increased use of NGVs can result in a decreased requirement on the volume of around 1.3 LNG tanks lower in 2014. Also, it shows that TDRs can be reduced by 0.4 for the city gas and by 0.15 for the total LNG in 2014. As a conclusion, we suggest that the promotion of NGVs may play an efficient role as a DSM strategy, and should be considered as a promising strategy to optimize the investment needs in LNG sector as well as an environmental protection measures. Lastly, we acknowledge that a transportation module in our model is based on a Korean government's NGVs promotion plan, not on a market function.

• Aerospace Engineering and Technology
• /
• v.10 no.1
• /
• pp.54-62
• /
• 2011

The pressurant mass required for propellant tank pressurization with operating condition variation was estimated by using the numerical model already developed for this purpose. The model was applied to the concept design results of KSLV-II first stage oxygen tank. The supplied pressurant temperature, oxygen volumetric flow rate, and the ratio of length to diameter of the tank were selected as variables. The required pressurant mass and mass flow rate, collapse factor, ullage temperature distribution were predicted, and the results showed that the pressurant temperature had the largest effect on the amount of the required pressurant mass. The pressurizing efficiency of the propellant tank was calculated through analyzing energy distribution in the ullage. It was found that the gas-to-wall heat transfer in the ullage was dominant, and much of the pressurant energy was lost to tank wall heating.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.5 no.3
• /
• pp.364-375
• /
• 2013

Contemporary lectures in undergraduate engineering courses typically focus on teaching major technical knowledge-based theories in a limited time. Therefore, most lectures do not allow the students to gain understanding of how the theories are applied, especially in Naval Architecture and Ocean Engineering departments. Shipyards require students to acquire practical ship design skills in undergraduate courses. To meet this requirement, two lectures are organized by the authors; namely, "Planning Procedure of Naval Architecture & Ocean Engineering" (PNAOE) and "Innovative Ship Design" (ISD). The concept of project-based and collaborative learning is applied in these two lectures. In the PNAOE lecture, sophomores receive instruction in the designing and building of model ships, and the students' work is evaluated in a model ship contest. This curriculum enables students to understand the concepts of ship design and production. In the ISD lecture, seniors learn how to develop their creative ideas about ship design and communicate with members of group. They are encouraged to cooperate with others and understand the ship design process. In the capstone design course, students receive guidance to facilitate understanding of how the knowledge from their sophomore or junior classes, such as fluid mechanics, statics, and dynamics, can be applied to practical ship design. Students are also encouraged to compete in the ship design contest organized by the Society of Naval Architects of Korea. Moreover, the effectiveness of project-based and collaborative learning for enhancing interest in the shipbuilding Industry and understanding the ship design process is demonstrated by citing the PNAOE and ISD lectures as examples.

• Journal of KIISE
• /
• v.43 no.9
• /
• pp.1015-1025
• /
• 2016

Currently, software testing is becoming increasingly important in the industrial field and a large body of research supports the improvement of efficient software testing. Model-based testing is generally used to formalize user requirement data for test design. Complex system that includes loop and concurrency has a high probability of path explosion problem. Specially, as threads are added to concurrency, test scenarios have also increased exponentially. However, it is difficult to solve this problem using existing techniques. In this paper, we propose novel path-search technique that focuses on behavioral features of concurrency path in order to avoid path explosion problem. A system that contains concurrent paths is represented by activity diagram in case study section. Efficiency of our study is shown through comparison with several generated test scenarios of other studies. The result indicate that our approach is efficient for finding faults in loop and concurrency with fewer test scenario.

• The Korean Journal of Food And Nutrition
• /
• v.29 no.2
• /
• pp.290-299
• /
• 2016

This study was conducted to determine the association between dietary calcium intake and biomarkers related to lipid and glucose metabolism and inflammation in Korean patients with type 2 diabetes. Seventy-five subjects (41 males, 34 females) were recruited from a group of patients who had visited the department of endocrine medicine. Data on anthropometric characteristics, clinical indices such as hemoglobin A1c and C-reactive protein (CRP), and dietary nutrient intakes were collected. Subjects were divided into three groups on the basis of their calcium intake [< EAR (below estimated average requirement), EAR-RNI (between EAR and recommended nutrient intake), > RNI (above RNI)]. Average calcium intake of < EAR, EAR-RNI, > RNI groups were $462.7{\pm}18.7$, $649.7{\pm}12.8$, and $895.7{\pm}21.7mg$, respectively. Energy intake was not different among groups but intakes of protein, total and saturated fatty acids were significantly higher in > RNI group than < EAR group. Analysis of covariance revealed that HDL cholesterol level was significantly higher in EAR-RNI group, as compared to < EAR group after adjustment with confounders such as age, sex, BMI and energy intake (p < 0.05). Levels of CRP and homeostasis model assessment 2-insulin resistance (HOMA2-IR) were significantly lower in EAR-RNI group. Total cholesterol level was higher in EAR-RNI and > RNI groups, although within the normal range. Our results suggest that dietary calcium intake may influence the levels of HDL-cholesterol, CRP and HOMA2-IR and subsequently, help management/treatment of type 2 diabetes patients.

• Journal of Korea Society of Industrial Information Systems
• /
• v.8 no.2
• /
• pp.7-13
• /
• 2003

The Internet presents a unique platform for disseminating digital content such as music, video, games, software, text, business and proprietary corporate information. It promises ubiquitous access, while at the same time fundamentally challenging the traditional rules of ownership and distribution of content. In such environment, safe protection and proper delivery of digital content would be a crucial requirement toward a new e-business model. Research on the Digital Rights Management (DRM) focuses on filling this functional vacancy of the market transition by providing a more viable business model based. XrML(eXtensible Rights Markup Language) provides a universal tool for specification of rights, fees, and issuing conditions(licenses) associated with the use and protection of digital content. ContentGuard has developed XrML to unify the Digital Rights Management(DRM) specifications and encourage interoperability. It seems that all working groups of DRM agree to use XrMl for their right description language.