• Journal of the Korean Electrochemical Society
• /
• v.3 no.1
• /
• pp.19-24
• /
• 2000

It is increasingly necessary to use poly-Si n's as high resolution and integration of Tn for LCD. Excimer Laser Crystallization (ELC) of a-Si is mainly used as a low temperature process. But the ELC method for the fabrication of poly-Si has the eruption problems associated with hydrogen in the a-Si film. So we need a dehydro-genation process additionally. Hydrogen in a-Si film can degrade the quality of poly-Si film and electrical properties of device due to the hydrogen eruption and voids which occur during the excimer laser annealing. In this study, we propose mesh-type PECVD as the a-Si film deposition method for achieving the low concentration hydrogen. Mesh-type PECVD was found to reduce the hydrogen content substantially. We could obtain a as-deposited a-Si film with hydrogen contents less than $1\%$ at $300^{\circ}C$. We also investigated the behavior by XeCl excimer laser annealing of a-Si fabricated by mesh-type PECVB. As a result, we were able to confirm the broad process window in contrast to the narrow process range typically obtained in ELC. Hydrogen eruption was not observed in poly-Si films after ELC These results suggests that mesh-type PECVD is a viable method to achieve the low hydrogen content a-Si and improve the process windows for ELC.

• Journal of Broadcast Engineering
• /
• v.11 no.1 s.30
• /
• pp.28-41
• /
• 2006

Due to the rapid development of multimedia appliances, the increasing amount of multimedia data enforces the development of automatic video analysis techniques. In this paper, a method of ToC generation is proposed for educational video contents. The proposed method consists of two parts: scene segmentation followed by scene annotation. First, video sequence is divided into scenes by the proposed scene segmentation algorithm utilizing the characteristics of educational video. Then each shot in the scene is annotated in terms of scene type, existence of enclosed caption and main speaker of the shot. The ToC generated by the proposed method represents the structure of a video by the hierarchy of scenes and shots and gives description of each scene and shot by extracted features. Hence the generated ToC can help users to perceive the content of a video at a glance and. to access a desired position of a video easily. Also, the generated ToC automatically by the system can be further edited manually for the refinement to effectively reduce the required time achieving more detailed description of the video content. The experimental result showed that the proposed method can generate ToC for educational video with high accuracy.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.48 no.5
• /
• pp.383-390
• /
• 2020

Wedge locks have been widely used for spaceborne electronics for mounting or removal of a printed circuit board (PCB) during integration, test and maintenance process. However, it can basically provide a mechanical constraint on the edge of the board. Thus, securing a fatigue life of solder joint for electronic package by limiting board deflection becomes difficult as the board size increases. Previously, additional stiffeners have been applied to reduce the board deflection, but the mass and volume increases of electronics are unavoidable. To overcome the aforementioned limitation, we proposed an application of multi-layered PCB sheet with viscoelastic adhesive tapes to implement high-damping capability on the board. Thus, it is more advantageous in securing the fatigue life of package under launch environment compared with the previous approach. The basic characteristics of the PCB with the multi-layered sheet was investigated through free-vibration tests at various temperatures. The effectiveness of the proposed design was validated through launch vibration test at qualification level and fatigue life prediction of electronic package based on the test results.

• Science of Emotion and Sensibility
• /
• v.23 no.3
• /
• pp.79-90
• /
• 2020

The inconsistency in different sensory information causes virtual reality (VR) sickness. This research verifies whether the consistent sensory information reduces VR sickness within treadmill-based virtual reality. Furthermore, we examined the inconsistency between the visually perceived walking speed by optical flow in VR and the physically perceived walking speed in treadmill walking on VR sickness. In Experiment 1, participants reported VR sickness levels while experiencing an increase in the virtual reality. We compared the VR sickness level reported on the standing still condition with that on the treadmill-walking condition. Based on our results, less VR sickness and more sense of presence and immersion were reported on the treadmill-walking condition than on the standing still condition. In Experiment 2 and Experiment 3, the effect of inconsistency between perceived visual speed and perceived walking speed on VR sickness was examined. Interestingly, participants reported less sickness when the perceived visual speed was faster than the perceived walking speed, compared to when the sense of speed was consistent. These results imply that allowing participants to walk on a treadmill while experiencing virtual reality reduces VR sickness. Hence, the perceived visual-walking speed consistency is not necessarily required to reduce VR sickness.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.6 no.1
• /
• pp.144-155
• /
• 1996

During the 1990s the workplace has grown more complex and business competition has increased world-wide. All organizations, whether for-profit or non-profit have been forced to respond to market changes. More advanced information and technology, greater product diversity, shorter product life cycles, increased quality requirements, more regulation oversight, decreasing productivity, more competitors, and increasing overhead costs have motivated organizations to focus on ways to deliver products cheaper, better, and faster. Many organizations are searching for ways to reduce costs through downsizing, reengineering business processes, implementing quality management, outsourcing, and improving cost management. Support departments that provide services internal to an organization such as human resources, legal, and environmental, safety, and health (ES&H) are often the first organization targeted for cost reduction and cost control initiatives because these functions are part of a rapidly increasing overhead cost. Recently, ES&H functions are incresingly being integrated into the business of business to contribute value to organization beyond mere compliance with ES&H regulations. The discussions and development of the ISO compatible Environmental Management Standards or Occupational Safety and Health Management Standards is another impetus to integrate ES&H function into the business of business. Thus, ES&H professional need new skills to analyze the cost of their function and communicate the value of the products and services they provide. In recent years, the need for and the importance developing cost management and business skills by ES&H professionals have been emphasized in the literature. Communicating with decision makers in terms of cost and value to the organization, and by using business language and business arguments is the first step toward effectively integrating ES&H activities into the business of business. Activity-based costing (ABC) is a cost management method that measures the cost of a product or service based on the actual use of resources by activities, and based on the actual amount of activities used to produce a product or service. ABC is recommended as a tool for managers of ES&H organizations to determine the cost of developing and providing ES&H products within a for-profit firm or non-profit agency. This paper discusses the trend of integration of ES&H functions into the mainstream of business activities within an organization. The general principles of treditional cost accounting are presented as a bases for understandging why and how ABC will provide more accurate estimates of cost. The principles and concepts of ABS are presented as a tool for determining more accurately the true cost of ES&H products and services.

• Asian Journal of Atmospheric Environment
• /
• v.12 no.3
• /
• pp.232-243
• /
• 2018

The construction, development and maintenance of an economically, environmentally and socially sustainable campus involves the integration of measuring tools and technical information that invites and encourages the community to know the actual state to generate positive actions for reducing the negative impacts over the local environment. At the Universidad Nacional de Colombia - Campus $Bogot{\acute{a}}$, a public area with daily traffic of more than 25000 people, the Environmental Management Bureau has committed with the monitoring of the noise pollution and air quality, as support to the campaigns aiming to reduce the pollutant emissions associated to the student's activities and campus operation. The target of this study is based in the implementation of mobile air quality and sonometry monitoring equipment, the mapping of the actual air quality and noise pollution inside the university campus as a novel methodology for a sub-area inside a megacity. This results and mapping are proposed as planning tool for the institution administrative sections. A mobile Kunak$^{(R)}$ Air & OPC air monitoring station with the capability to measure particulate matter $PM_{10}$, $PM_{2.5}$, Ozone ($O_3$), Sulfur Oxide ($SO_2$), Carbon Monoxide (CO) and Nitrogen Oxide ($NO_2$) as well as Temperature, Relative Humidity and Latitude and Longitude coordinates for the data georeferenciation; and a sonometer Cirrus$^{(R)}$ 162B Class 2 were used to perform the measurements. The measurements took place in conditions of academic activity and without it, with the aim of identify the impacts generated by the campus operation. Using the free code geographical information software QGIS$^{(R)}$ 2.18, the maps of each variable measured were developed, and the impacts generated by the operation of the campus were identified qualitative and quantitively. For the measured variables, an increase of around 21% for the $L_{Aeq}$ noise level and around 80% to 90% for air pollution were detected during the operation period.

• Journal of KIISE:Information Networking
• /
• v.34 no.2
• /
• pp.110-119
• /
• 2007

Mobile IPv6 (MIPv6) enables a mobile node (MN) to maintain its connectivity with a correspondent node (CN) while changing its point of attachment. In MIPv6, packets sent from a CN to a MN during handover are lost. Several mechanisms including FMIPv6 and HMIPv6 have been proposed in order to minimize packet loss. However, such mechanisms still suffer from performance degradation due to not only packet loss but also out-of-sequence packets. In this paper, we propose I-FHMIPv6 to resolve packet loss as well as the out-of-sequence packet problem. In I-FHMIPv6, the flush message is newly defined in order to notify a home agent (HA) or CN of the fact that the binding cache entry of a MN is about to be updated. A MN receiving the flush message can know that there is no more packets transmitted via the previous route, which resolve the out-of-sequence packet problem. Moreover, with the proposed mechanism, we can minimize packet loss by integrating FMIPv6 and HMIPv6 efficiently. I-FHMIPv6 is evaluated by performing simulations, and the simulation results show that I-FHMIPv6 outperforms FMIPv6 and HMIPv6.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.31 no.2
• /
• pp.202-209
• /
• 1998

A three-dimensional numerical method based on the Green's integral equation is developed to predict the motion response and drift force in waves for the ocean monitoring facilities. In this method, we use source and doublet distribution, and triangular and rectangular eliments. To eliminate the irregular frequency phenomenon, the method of improved integral equation is applied and the time-mean drift force is calculated by the method of direct pressure integration over the body surface. To conform the validity of the present numerical method, some calculations for the floating sphere are performed and it is shown that the present method provides sufficiently reliable results. As a calculation example for the real facilities, the motion response and the drift force of the vertical cylinder type ocean monitoring buoy with 2.6 m diameter and 3,77 m draft are calculated and discussed. The obtained results of motion response can be used to determine the shape and dimension of the buoy to reduce the motion response, and other data such as the effect of motion reduction due to a damper can be predictable through these motion calculations. Also, the calculation results of drift force can be used in the design procedure of mooring system to predict the maximum wave load acting on the mooring system. The present method has, in principle, no restriction in the application to the arbitrary shape facilities. So, this method can be a robust tool for the design, installation, and operation of various kinds of the floating-type ocean monitoring facilities.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.12
• /
• pp.41-52
• /
• 2016

Prescription, pickup, and acting information from the ward are stored in a hospital database, and can be accessed and retrieved by the relevant departments. Frequent inquiries from many departments can cause a great load on the hospital information system. When the nursing and care services are integrated, the real-time pickup and acting tasks are also increased, which may lead to an increase in database inquiries, thereby increasing the amount of information being transferred. To effectively solve this inefficiency problem, we aimed to develop a nursing and care integrated information system that excludes database inquiries and incorporate a method that transmits pickup and acting information in real-time. Because the new system increases the workload and responsibility, we developed a ward acting dashboard so that every ward employee can determine all the acting situations of patients in real-time to improve the quality of services. We designed a database by concentrating on the pickup and acting business procedures, and applied real-time web techniques to enable pickup and acting information to be delivered instantly. Through our implementation, we were able to reduce the inquiry time and transmission amount significantly compared with the existing method.

• Journal of the Korean Vacuum Society
• /
• v.11 no.1
• /
• pp.50-58
• /
• 2002

The growth of GaN films on Si substrate has many advantages in that Si is less expensive than sapphire substrate and that integration of GaN-based devices with Si substrate is easier The difference of lattice constant and thermal expansion coefficient between GaN and Si is larger than those between GaN and sapphire. However, which results in many defects into the grown GaN. In order to obtain high duality GaN films on Si substrate, we need to reduce defects using the buffer layer such as AlN. In this study, we prepared three types of AlN buffer layer with various crystallinity on Si (111) substrate using MOCVD, Sputtering and MOMBE methods. GaN was grown by MOCVD on three types of AlN/Si substrate. Using TEM and XRD, we carried out comparative investigation of growth and properties of GaN deposited on the various AlN buffers by characterizing lattice coherency, crystallinity, growth orientation and defects formed (voids, stacking faults, dislocations, etc). It is found that the crystallinity of AlN buffer layer has strong effects on growth of GaN. The AlN buffer layers grown by MOCVD and MOMBE showed the reduction of out-of-plane misorientation of GaN at the initial growth stage.