• Journal of the Korea institute for structural maintenance and inspection
• /
• v.22 no.4
• /
• pp.1-9
• /
• 2018

The development of new technology and process in industrial Plant which builds integrated structures, facilities and systems. Has become a key element for strengthening its competitiveness. Although domestic industrial Plant has demonstrated excellence in technology with a persistent increase in order quantity and orders received, the technology gap between countries has narrowed due to global construction trend. Therefore, it is necessary to develop new technology that could help overcome constraints and limitations of the current one to follow the trend in the age of unlimited competition. This study has focused on assembly technology of Pipe-rack joint connection in an effort to strengthen technological competitiveness in industrial Plant. Through an analysis of earlier studies on Pipe-rack and a coMParative analysis of strengths and weaknesses of current assembly technology of it, a new design plan has been made to improve it efficiently. In doing this, standards for design factors of both structural and performance features have been drawn, and value of stress, strain, moment and rotation has been calculated using finite element analysis. As a result, installation technology of modular type Pipe-rack, which has not been developed in Korea and is differentiated from the current one, has been developed. It is considered that the technology reduces work time and saves cost due to simplified joint connection of steel structure, unlike the current one. Moreover, since it is installed without a welding process in the field, industrial accidents would be reduced, which is likely to have economic competitiveness and satisfy.

• Korean Journal of Optics and Photonics
• /
• v.16 no.3
• /
• pp.209-216
• /
• 2005

A new second generation advanced thermal imager, which can be used for battle tank sight has been developed by ADD. This system uses a $480\times6$ TDI HgCdTe detector, operating in the $7.7-10.3{\mu}m$ wavelength made by Sofradir. The IR optics has dual field of views such as $2.67\times2^{\circ}$ in NFOV and $10\times7.5^{\circ}$ in WFOV. And also, this optics is used for athermalization of the system. It is certain that our sensor can be used in wide temperature range without any degradation of the system performance. The scanning system to be able to display 470,000 pixels is developed so that the pixel number is greatly increased comparing with the first generation thermal imaging system. In order to correct non-uniformity of detector arrays, the two point correction method has been developed by using the thermo electric cooler. Additionally, to enhance the image of low contrast and improve the detection capability, we have proposed the new technique of histogram processing being suitable for the characteristics of contrast distribution of thermal imagery. Through these image processing techniques, we obtained the highest quality thermal image. The MRTD of the LWIR thermal sight shows good results below 0.05K at spatial frequency 2 cycles/mrad at the narrow field of view.

• The Bulletin of The Korean Astronomical Society
• /
• v.39 no.1
• /
• pp.49.1-49.1
• /
• 2014

The NISS (Near-infrared Imaging Spectrometer for Star formation history) onboard NEXTSat-1 is the near-infrared instrument onboard NEXTSat-1 which is being developed by KASI. The imaging low-resolution spectroscopic observation in the near-infrared range for nearby galaxies, low background regions, star-forming regions and so on will be performed on orbit. After the System Requirement Review, the optical design is changed from on-axis to the off-axis telescope which has a wide field of view (2 deg. ${\times}$ 2 deg.) as well as the wide wavelength range from 0.95 to $3.8{\mu}m$. The mechanical structure is considered to endure the launching condition as well as the space environment. The design of relay optics is optimized to maintain the uniform optical performance in the required wavelength range. The stray light analysis is being made to evade a light outside a field of view. The dewar is designed to operate the infrared detector at 80K stage. From the thermal analysis, we confirmed that the telescope can be cooled down to around 200K in order to reduce the large amount of thermal noise. Here, we report the current status of the NISS development.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.11 no.3 s.55
• /
• pp.23-31
• /
• 2007

Fast bridge construction has been increasingly needed according to the changed construction environment. This paper deals with quasi-static tests on precast piers for bridge substructures. One of the most crucial aspect of the design of precast prestressed concrete bridge piers is the seismic performance. Seven precast pier elements were fabricated. The amount of prestressing bars, the prestressing force, and the location and number of the joint between segments were the main test parameters. Test results showed that the introduced axial prestress made the restoration of the deformation under small lateral displacement and minor damage. However, there was no effect of the prestress when the plastic hinge region was damaged severely due to large lateral displacement. Judging from the observed damage, the design of the joints in precast piers should be done for the first joint between the foundation and the pier segment. The amount of the necessary prestressing steel may be designed to satisfy the P-M diagram according to the service loads, not by having the same steel ratio as normal RC bridge piers. In order to satisfy the current required displacement ductility, it is necessary to have the same amount of the transverse reinforcements as RC piers. As the steel ratio increases, the energy absorption capacity increases. The number of joints showed a little influence on the energy absorption capacity.

• The Journal of Korean Academy of Prosthodontics
• /
• v.32 no.4
• /
• pp.526-552
• /
• 1994

The extent and direction of movement of removable partial dentures during function are influenced by the nature of the supporting structures and and the design of the prosthesis. Since forces are transmitted to the abutment teeth through occlusal rests, guide planes and direct retainers during functional movements, proper design based on the avaialble research data will maintain the health of abutment teeth and their supporting structures. The purpose of this in vitro study is evaluating stress distribution clinically around the abutment teeth prepared following 4-type clasping systems for unilateral free-end removable partial dentures. Three-Dimensional Photoelastic Stress Analysis method was used because it shows a visual display of stresses of the simulated abutment teeth and residual ridges and reveals stress concentration that can be read at any given points in terms of direction and magnitude. For this study, the author fabricated 4 mandibular photoelastic epoxy models missing left 1st and End molar. Epoxy models were duplicated and 4 unilateral removable partial dentures were construe- ted in accordance with 4-type direct retainers. Unilateral free-end removable partial dentures were positioned on their own models. 6kg force was loaded on the every removable partial dentures of the epoxy model on the central fossa of mandibular left 1st molar vertically by the loading device. After the stress was frozen in a stress freezing furnace, 6 specimens of 6-mm thickness were made from every epoxy model and examined with the circular polariscope. The results were as follows : 1. Generally I-bar clasp revealed the most favorable stress distribution around the abutment teeth. 2. At the end portion of the free-end ridge, Back action clasp showed the highest stress concentration at the bucco-lingual and top portions of the residual alveolar ridge. 3. At the distal area of the abutment teeth, Akers clasp and Roach clasp showed higher stress concentration bucco-lingually and apically than the others. 4. To the abutment tooth, I-bar clasp showed the least stress distribution bucco-lingually but the others showed irregular stress distribution. 5. At the mesial area of the abutment teeth, the order of effective stress distribution was I-bar clasp, Back-action clasp, Akers clasp and Roach clasp. There was big difference of stress distribution between them. 6. At the right 2nd premolar and 1st molar, the stress concentration of Akers clasp was a little high but that of I-bar clasp was low.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.32 no.2
• /
• pp.106-121
• /
• 2020

In order to make harbor outskirt facilities robust using the reliability-based design, probabilistic models of wave heights at varying stage of shoaling process optimized for Korean sea waves are prerequisite. In this rationale, we numerically simulate the nonlinear shoaling process of random waves over the beach with a sandbar at its foreshore. In doing so, comprehensive numerical models made of spatially filtered Navier-Stokes Eq., LES [Large Eddy Simulation], dynamic Smagorinsky turbulence closure were used. Considering the characteristics of swells observed at the east coast of Korean Peninsula, random waves were simulated using JONSWAP wave spectrum of various peak enhancement coefficients and random phase method. The coefficients of probabilistic models proposed in this study are estimated from the results of frequency analysis of wave crests and its associated trough detected by Wave by Wave Analysis of the time series of numerically simulated free surface displacements based on the threshold crossing method. Numerical results show that Modified Glukhovskiy wave height distribution, the most referred probabilistic models at finite water depth in the literature, over-predicts the occurring probability of relatively large and small wave heights, and under predicts the occurrence rate of waves of moderate heights. On the other hand, probabilistic models developed in this study show vary encouraging agreements. In addition, the discrepancy of the Modified Glukhovskiy distribution from the measured one are most visible over the surf zone, and as a result, the Modified Glukhovskiy distribution should be applied with caution for the reliability-based design of harbor outskirt facilities deployed near the surf-zone.

• Archives of design research
• /
• v.18 no.3 s.61
• /
• pp.209-218
• /
• 2005

Consciously or not, producers have to make many aesthetic choices in creative process of video production. If there are general acceptable aesthetic principles to make right choice it would be guideline of aesthetic decision to somewhat reduce mistakes and errors in the process. This paper proposes a theoretical approach on establishing the media aesthetic principle of 3D animation camera working, which is the most suitable for animation production context. We describe the Herbert Zettl's applied media aesthetics related directly to the camera, which is about the two-Dimensional field focusing on aspect radio and forces within the screen, three-dimensional field focusing on depth, volume, and four-dimensional field focusing on time and motion. In order to have theoretical approach we made an analysis on comparing a camera working of movie with 3D computer animation's one, and reconstructed these basic principles to be suited for the 3D animation production. When applied media aesthetics of the traditional camera working are applied to the 3D animation production, it could be an efficient guideline for it. Futhermore, if we develop the research for the relationship with various visual languages with the basis of these principles, the theory of creative picture composition method for the 3D animation production will be logically and systematically established.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.9
• /
• pp.2402-2408
• /
• 2009

This study conducted a static tensile test in order to prevent the lowering of load carrying capacity caused by critical sections made by over bolt holes in the base plate and the cover plate of steel member joints using high-tension bolts. The change of the load carrying capacity of joints was examined by comparison of the maximum load on joint fracture obtained from the tensile test with critical section rate and design strength. According to the results, the rate of decrease in strength was higher when the critical section rate was high, and in particular, decrease in strength was affected much more by critical sections in the base plate than by those in the cover plate. In high-tension bolt joints using over bolt holes for the base plate and the cover plate, load carrying performance was somewhat lower than that in joints using standard bolt holes, but the maximum tensile strength on facture was over 15% higher than design fracture strength. According to the results of this study, the use of over bolt holes in high-tension bolt joints had an insignificant effect on the lowering of load carrying capacity, so the allowance of over bolt holes in the joints of steel members is expected to enhance to the economy and efficiency of the works.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.38 no.3
• /
• pp.50-63
• /
• 2020

This research examines the extent to which the Urban Regeneration Project has on not just physical environments and settings, but also non-physical elements such as history, culture, community, and the general economy, in addition to the analysis and categorization of its historical-cultural contents. In order to achieve this, the historical-cultural content were defined and categorized by analyzing a total of thirty-three characteristics of the Urban Regeneration Project. The analysis showed three things. First: historical-cultural business seen as a purpose of the Urban Regeneration Project comes to be subdivided into three different categories: the Arts & Cultural, the Economic Cultural, and the Historical Heritage. Second: the historical-cultural content as the leading projects were generally executed in collaboration with physical regenerations. Third: In the initial stages of the project, many businesses made crafty use of an eclectic of historical-cultural content. However, some conflicts between public officials and residents could be observed. In conclusion, the comprehensive use of historical-cultural contents in carrying out Urban Regeneration Project must have using historical-cultural content must have physical regeneration at its core, but also go above and beyond, expanding to an Human Resource-regeneration that is comprised of nonphysical regeneration as well as a governing body. Furthermore, hefty research on the development and appropriate usage of historical-cultural content is critical, as the 4th Industrial Revolution unfold before the world.

• Journal of Distribution Science
• /
• v.13 no.1
• /
• pp.35-46
• /
• 2015

Purpose - This paper attempted to investigate the relationships among the perception of job insecurity and organizational effectiveness, and it examines these relationships while considering the moderating effect of trust in the manager and self-efficacy. Job insecurity is an independent variable, organizational effectiveness aspects (job satisfaction, organizational commitment, and turnover intention) are dependent variables, and trust and self-efficacy are moderators. Research design, data, and methodology - Regression analysis was used to verify the effects. The measurement items were already deemed as reliable and valid in the previous study, but for this purpose, some modifications were made. To examine the model, this study relied on the samples chosen from Korean employees in the six franchise business firms. The survey was conducted on 288 workers. Each question is based on a 5-point Likert type scale. The data were analyzed using SPSS 18.0. Results - The results of the study are summarized as follows. First, job insecurity has an influence on organizational effectiveness aspects (negatively on job satisfaction, negatively on organizational commitment, and positively on turnover intention). Second, analyzing the moderating effect of trust, trust in manager is mediated between job insecurity and organizational effectiveness aspects (on organizational commitment and on turnover intention). However, employees' trust in manager had no significant moderating effect on the job insecurity-job satisfaction relationship. Third, self-efficacy is mediated between job insecurity and organizational effectiveness aspects (on job satisfaction, on organizational commitment, and on turnover intention). Conclusions - First, it is necessary to be aware of the seriousness of employees' job insecurity in franchise firms, which have played a pivotal role in national economic growth, and to create a detailed plan for reducing insecurity and actively implementing it. To this end, the franchise companies should implement efficiency efforts such as obtaining an appropriate capacity of equipped personnel and a training program. Second, there are moderating effects of self-efficacy and trust in the relationship between job insecurity and organizational effectiveness. Depending on business conditions, stability and instability can only be experienced in the organizations of franchise companies. This can give rise to instability in employment. Therefore, it is necessary to develop and utilize a system that can be minimized with a change in the new awareness of employment instability. After all, a good leader (manager) must accumulate personal trust and build up a core competence that is necessary to become competent in the field himself. Even if you lack the material resources to improve performance, if the leader with the core competencies (e.g., technical/management /organization/marketing/design) can gain the trust of the supervisor, you can get a good organizational performance. Therefore, you should foster a healthy organizational culture through education such as leadership training and employee training to be built on trust between the leaders and the employees. In addition, you need to focus on HRD&M training in order to increase the self-efficacy of the supervisor.