• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.2
• /
• pp.949-954
• /
• 2013

Generally, structural plates under axial compression should be stiffened by longitudinal stiffeners in order to enhance the buckling strength. Though U-shaped ribs would be more efficient for the stiffened plate system, there is in the absence of a proper design guides or relevant research results. Thus this study is aimed to examine the local buckling behavior of stiffened plates with U-section ribs. 3-dimensional analysis models which include 3 types of U-shaped longitudinal stiffeners were simulated by using the finite element code ABAQUS. The bifurcation analysis were conducted and then the buckling analysis results are compared with the theoretical equation values. It is found that the rotational constraint effect provided by the U-ribs should increase the local buckling strength. Some features drawn from a series of parametric study results are summarized.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.4
• /
• pp.194-201
• /
• 2004

Optical fibers are indispensable fer optical communication systems that transmit large volumes of data at high speed. But the aligning technology under the sub-micron accuracy is required for the precise axis adjustment and connection. For the purpose of precise alignment of the optical arrays, in this research, we have developed the 12-axis(with 8 automated axis and 4 manual axis) automatic optical fiber alignment system including the image processing-based searching system, the automatic loading system using the robot and the suction toot and the automatic UV bonding system. In order to obtain the sub-micron alignment accuracy, two 4-axis PC-based motion controllers and the two 50nm resolution 6-aixs micro-stage actuated by micro stepping motors are adopted. The fiber aligning procedure consists of two steps. Firstly, the optical wave guide and an input optical array are aligned by the 6-axis input micro-stage with the IR camera. The image processing technique is introduced to reduce primary manual aligning time and result in achieving the 50% decrease of aligning time. Secondly, the IR camera is replaced by the output micro-stage and a wave guide and two optical arrays are aligned simultaneously before the laser power intensity delivered to the optical powermeter reached the threshold value. When the aligning procedure is finished, the wave guide and arrays are W bonded. The automatic loading/unloading system is also introduced and the entire wave guide handing time is reduced significantly compared to the former commercial aligning system.

• Korean Management Science Review
• /
• v.32 no.4
• /
• pp.109-133
• /
• 2015

This paper considers the allocation and engagement scheduling of air defense missiles by using MIP (mixed integer programming). Specifically, it focuses on developing a realistic MIP model for a real battle situation where multiple enemy missiles are headed toward valuable defended assets and there exist multiple air defense missiles to counteract the threats. In addition to the conventional objective such as the minimization of surviving target value, the maximization of total intercept altitude is introduced as a new objective. The intercept altitude of incoming missiles is important in order to minimize damages from debris of the intercepted missiles and moreover it can be critical if the enemy warhead contains an atomic or chemical bomb. The concept of so called the time window is used to model the engagement situation and a continuous time is assumed for flying times of the both missiles. Lastly, the model is extended to simulate the situation where the guidance radar, which guides a defense missile to its target, has the maximum guidance capacity. The initial mathematical model developed contains several non-linear constraints and a non-linear objective function. Hence, the linearization of those terms is performed before it is solved by a commercially available software. Then to thoroughly examine the MIP model, the model is empirically evaluated with several test problems. Specifically, the models with different objective functions are compared and several battle scenarios are generated to evaluate performance of the models including the extended one. The results indicate that the new model consistently presents better and more realistic results than the compared models.

• The Journal of the Korea Contents Association
• /
• v.13 no.12
• /
• pp.1017-1025
• /
• 2013

As various types of regional festivals are contributing to the growth of local economy, promoting the culture, and enhancing the region's images, representative festivals are getting more important for local governments. This study analyzed the correlation between satisfaction on festivals' attractiveness and images of the region, based on an actual field study taken with respondants who visited 2012 Anseong World's Folkloriada Festivals. Among various facets that affect festivals' attractiveness, 4 factors such as services aside from transportation and promotional guides, programs, convenient facilities, and food significantly affected tourists' satisfaction level. Tourists' satisfaction level was found to have significant impact on the enhancement of local images. Based on these findings, this paper suggests implications and limitation of the research as well as future directions for the study.

• Journal of Biomedical Engineering Research
• /
• v.28 no.1
• /
• pp.36-45
• /
• 2007

Today Human Personal Trainers are becoming very famous in this health conscious world. They teach user to achieve fitness goals in managed way. Due to their high fee and tight schedule they are unavailable to mass number of people. Another solution to this problem is to develop digital personal trainer portable instrument that may replace human personal trainers. We developed a portable digital exercise trainer device - BIOFIT that manages, monitors and records the user's physical status and workout during exercise session. It guides the user to exercise efficiently for specific fitness goal. It keeps the full exercise program i.e. exercises start date and time, duration, mode, control parameter, intensity in its memory which helps the user in managing his exercise. Exercise program can be downloaded from the internet. During exercise it continuously monitors the user's physiological parameters: heart rate, number of steps walked, and energy consumed. If these parameters do not range within prescribed target zone, the BIOFIT will alarm the user as a feedback to control exercise. The BIOFIT displays these parameters on graphic LCD. During exercise it continuously records the heart rate and number of steps walked every 10 seconds along with exercise date and time. This stored information can be used as treatment for the user by an exercise expert. Real-time ECG monitoring can be viewed wirelessly (RF Communication) on a remote PC.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
• /
• v.43
• /
• pp.169-198
• /
• 2009

This paper sees some legal phases of the forfaiting transactions performed by using bills of exchange (drafts) or promissory notes. It focuses on the issues of the endorsement without recourse and the aval under the Korean statute for such negotiable instruments which is enacted by succeeding to the Convention Providing a Uniform Law For Bills of Exchange and Promissory Notes (Geneva, 1930) of the League of Nations. This paper purposes to give basic legal guides for forfaiting participants in order for them to be able to prevent and solve some problems caused by lack of understanding for relevant rules of law. Forfaiting is a useful technic as it provides financing for international export businesses by enabling forfaiters to discount future payment obligations on non-recourse basis. It gives benefits to exporters by removing political, transfer and commercial risks of importers or their country. Also it protects exporters from the risks of the increase of interest rates and the fluctuation of exchange rate as well. In traditionally normal forfaiting transactions, exporter of goods generally takes promissory notes or accepted drafts from importers in payment for the price of goods. Further, when the exporter is not comfortable with the importer's credit or is not confident whether the importer will pay the accepted drafts or the promissory notes as they come due, the exporter nomally requires the importer to make the importer's bank (avalizer or guarantor) add an aval, which is made by the written expression of intention, the words of "per aval", and the guarantor's signature on the drafts or promissory notes. The exporter endorses without recourse to transfer the drafts or the promissory notes to the forfaiter, typically a bank, who purchases the drafts or the promissory notes without recourse.

• Journal of Powder Materials
• /
• v.20 no.5
• /
• pp.355-358
• /
• 2013

Micro trench structures are applied in gratings, security films, wave guides, and micro fluidics. These micro trench structures have commonly been fabricated by micro electro mechanical system (MEMS) process. However, if the micro trench structures are machined using a diamond tool on large area plate, the resulting process is the most effective manufacturing method for products with high quality surfaces and outstanding optical characteristics. A nonferrous metal has been used as a workpiece; recently, and hybrid materials, including polymer materials, have been applied to mold for display fields. Thus, the machining characteristics of polymer materials should be analyzed. In this study, machining characteristics were compared between nonferrous metals and polymer materials using single crystal diamond (SCD) tools; the use of such materials is increasing in machining applications. The experiment was conducted using a square type diamond tool and a shaper machine tool with cutting depths of 2, 4, 6 and 10 ${\mu}m$ and a cutting speed of 200 mm/s. The machined surfaces, chip, and cutting force were compared through the experiment.

• Journal of The Korean Association of Information Education
• /
• v.21 no.6
• /
• pp.647-656
• /
• 2017

Digital storytelling provides students with opportunities to plan and compose a story, and create a storytelling material using various digital technologies. Through digital storytelling activities, students can enhance competencies such as creativity, communication, critical thinking and collaboration, which are required for the digital generation in the future. The purpose of this research was to develop a digital storytelling model that guides students' activities related to the planning of a story and the creation of a digital material. The model classified 4 stages of activities(i.e. 'Preparing Activity', 'Planning and Composing a Story', 'Producing Storytelling Material' and 'Making a Presentation and Evaluating Storytelling Material'), and provided instructional guidances for each stage. Also various forms were presented for story planning, story table, evaluation among students and individual reflection journal.

• Journal of the Korea Institute of Building Construction
• /
• v.11 no.2
• /
• pp.171-180
• /
• 2011

As high-rise and irregularly shaped building structures have become a trend at home and abroad, BIM technology is now being developed and accepted widely. However, the BIM data and information generated in the design phase cannot be actively reutilized in the construction stage. This is because the major interests of construction companies include working process and cost estimation, while there is not usually enough BIM data created to support these activities. In order to resolve this issue, we need to set up BIM modeling guides that make it possible to extract correct quantity take-off from BIM data. Quality checks are also necessary to ensure that the resulting BIM data is correct. This study suggests ways of securing BIM quality for correct quantity take-off, which is critical for BIM technology applied to the building construction process and its cost estimation.

• Journal of the Korean earth science society
• /
• v.25 no.4
• /
• pp.222-231
• /
• 2004

The purpose of this study is to analyze the seventh curriculum textbooks and teacher's guides of high school science courses in relation to the generation (mechanism) of magma in subduction boundary and find the incorrect descriptions of the texts and the figures (illustrations) and then suggest some improved schemes. According to the result there are many discrepancies in definition of 'magma' among the textbooks and further little scientific explanations about the formation mechanism of magma in most textbooks, and even no descriptions about that. In addition, the figures are inconsistent with the description of the text and also have some incorrect depiction which might contribute to the forming and reinforcing misconceptions about Plate Tectonics as well as a volcanic activity in subduction boundary. On the basis of the previous researches, therefore, some improved schemes (text descriptions and figures) are suggested. The results of this study should be used as a reference for publishing science textbook, developing science curriculum, and teaching effectively in the high school.