• Journal of the Korea Society of Computer and Information
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• v.12 no.2 s.46
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• pp.209-220
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• 2007

Mobile devices become a pak of our daily life due to their versatility, such as the wireless phone calls, the wireless accessibility to Internet, the display of multimedia content, and the communication with nearby mobile devices. Third generation telecommunication service provides an easy access to the Internet for nubile devices. Mobile users pay a fee charged by the telecommunication provider based on the amount of data transferred. This paper introduces a special ad hoc network in which mobile devices cooperate each other to download an interesting content from the Internet in order to reduce the telecommunication cost. The mobile devices, called the peers, in the ad hoc network are assigned a portion of the target file, and are responsible for downloading the portion using their 3G connection. Then, the peers exchange their downloaded portion with other participating peers using their cost-free ad hoc connection in order to reconstruct the whole content. According to the simulation results, large number of participating peers saves the telecommunication cost up to 90% with as few as 10 peers, although it slightly increase the overall content reconstruction time.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.194-198
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• 2021

LoRa is a physical layer technology that is designed to provide a reliable long-range communication with introducing CSS and with introducing a loco parentis tree network. Since a leaf can utilize multiple parents at the same time with a single transmission, PDR increases logarithmically as the number of gateways increases. Because of the ALOHA-like MAC of LoRa, however, the PDR degrades even under the loco parentis tree topology similarly to the single-gateway environment. Our proposed method is aimed to achieve SDMA approach to reuse the same frequency in different areas. For that purpose, it elaborately controls each TxPower of the senders for each message in concurrent transmission to survive the collision at each different gateway. The gain from this so-called capture effect increases the capacity of resource-hungry LPWAN. Compared to a typical collision-free controlled-access scheme, our method outperforms by 10-35% from the perspective of the total count of the consumed time slots. Also, due to the power control mechanism in our method, the energy consumption reduced by 20-40%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3A
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• pp.276-287
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• 2004

An ad hoc network is infra(Base Sstation or Access Point) free wireless mobile communication technology. Mobile nodes function as routers and servers in ad hoc networks. Many routing protocols for ad hoc network have been proposed. If any route is broken owing to moving node, source must repair broken route again. But route repair technology after route collapses is not suitable to transmit real-time data packet for QoS guarantee. So this paper presents route repair technology that prevents route from breaking. If intermediate node moves to critical section, the node issues handoff packet and sends the packet to the next node. After next node receives handoff packet, the node broadcasts route request packet to the previous node for intermediate node. Finally, even if intermediate node moves out of the routing region, the source can continuously transmit data packets to the destination through the new path.

• Journal of the Korean Institute of Landscape Architecture
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• v.50 no.5
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• pp.13-29
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• 2022

According to the revision of the Convenience Act for Persons with Disabilities, parks and park facilities where the first park development plan is established after December 4, 2021 are mandatory, and parks must be equipped with convenience facilities for the disabled. Hence, this study aims to derive the improvements of the park evaluation index by analyzing the park certification evaluation index, the building certification evaluation index of park facilities, and the evaluation reports of the current certification status cases. As a research method, first, the certification of parks and park facilities were compared and reviewed with the Park Green Act, and differences in the certification process and certification performance were compared and analyzed. Second, differences and common items were derived by analyzing barrier free (BF)-certification evaluation indicators for parks and buildings. Third, improvement plans were derived after analyzing differences and problems in 4 BF-certified parks and four building certification cases of park facilities in certified parks, focusing on the self-evaluation report and examination results. As a result of analyzing the park and building evaluation indicators, the items for which the evaluation purpose, evaluation method, and evaluation items were commonly applied to 7 access roads for each facility, 5 parking areas for the disabled, 2 guide facilities for information facilities, 14 in 5 categories of sanitation facilities, and 1 for other facilities. In the case of sanitation facilities, there is no case where it was evaluated as a park. If the park does not have an attached toilet, the park is certified as a building. Hence, it would be essential to establish the concept of an attached toilet and discuss the application of the evaluation index on the park sanitation facility. The score of buildings in parks and park facilities was lower than that of the self-evaluation results, and the certification grades of buildings declined in three cases. The items with the highest standard deviation were BF walking continuity for parks and the path to the main entrance among access roads for buildings. As a result of analyzing the park and building evaluation results of 19 common evaluation items except for sanitary facilities, the difference in the grades of the evaluation items for each case site except for one item appeared. Therefore, applying common detailed calculation criteria for items evaluated in common with parks and buildings is needed. Since sanitation facilities have no cases of park certification and are not certified as buildings, it is essential to establish the concept of attached toilets and discuss the application of park sanitation evaluation indicators. It is necessary to develop an evaluation index suitable for the characteristics of the park, such as adjusting the items that are not evaluated in parks and establishing an evaluation index considering the ones of parks. It expects that this study would be used as primary data for improving park certification indicators.

• Journal of Korean Library and Information Science Society
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• v.44 no.2
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• pp.315-343
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• 2013

Public works has been created by the taxes of the people, so free access and use of public works without charge in the public sector must be guaranteed for the benefit of the public. To do this, above all, a legal basis for solving the problems of the process for copyright should be to establish. Therefore, this study examined the legal concept of public works and the concept and scope of public institutions. And this study, as legislation case to limit the copyright protection of public works, analyzed the relevant provisions of copyright law and the recent revised plan in the U.S., UK, and Germany. And then I analyzed the regulations for limitation of copyright protection of current copyright law and the draft of copyright law on public works in Korea. Based on the results of these analyses, this study suggested the legal revised plan to expand significantly the limitations of copyright in order to activate the use of public works in the library.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.429-431
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• 2014

Raspberry Pi is in the UK (Paspberry Pi) Foundation created a compact / Cheap PC and was developed as part of the educational project. RCA connection jack and has been released in March 2012 was also sold out in one hour. Raspberry Pi Linux kernel based operating system called Raspberry Pi using optimized Raspbian Debian-based operating systems are often used to be free. Raspberry Pi is currently in the field of IoT with the board quite Cubie limelight and Cubie board holds more data. Arduino is quite easy to reach and access to the avr but impossible to include any custom code associated to a library and customize drawbacks must be solved only. Raspberry Pi using the Raj Caribbean and limitations of low cost, but there is a small output. So, for a combination of the two, with GPOI was reminiscent of hardware control. In this paper, using GPIO Cooking Hacks RaspberryPi board for controlling input and output by using the shield is insufficient expansion raspberry pie was confirmed that the good operation was verified.

• Journal of Appropriate Technology
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• v.6 no.2
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• pp.146-150
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• 2020

Assistive technologies for people with disabilities are often marginalized in the Fourth Industrial Revolution. In this paper, we intend to present the possibility of acquiring tactile information through the tactile display adapting an electromagnetic actuator. The multi-layered display designed for tactile communication has innovatively narrowed the size and spacing of cells in order to express pictures, maps, and graphics. This display has enabled the visually impaired to touch two-dimensional information combining with other assistive technologies so that. It would also provide a technical source of access to STEM education (Science, Technology, Engineering, and Mathematics) so that students will perform better and be better prepared for advanced education. Moreover, it can be applied to public infrastructure and transportation in smart-city projects on the globe. Hence, this paper introduces the principle of Electromagnetic-actuator and how it can be utilized in many diverse areas.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.2B
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• pp.148-158
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• 2011

Stationary nodes and mobile nodes co-exist wireless sensor network(WSN) can provide variety of new services. The stationary sensor node acts not only the gathering the environmental sensing data but also a access point to bidirectional communication with numerous mobile sensor nodes(mobile node), and the mobile sensor nodes are installed inside mobile objects and identify the location in real-time and monitor the internal status of the object. However, only using the legacy WSN protocol, it is impossible to set up the stable network due to the several reasons caused by the free-mobility of the mobile nodes. In this paper, we suggest three methods to increase the hit-ratio of the asynchronous message delivery(AMD) among mobile nodes. We verified the performance of the suggested methods under the stationary-mobile co-existed WSN testbed.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.43 no.6 s.312
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• pp.1-8
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• 2006

Many researches on path planning and obstacle avoidance for the fundamentals of mobile robot have been done recently. Informations from various sensors can be used to find obstacles and plan feasible path. In spite of many solutions of finding optimal path, each can be applied in only a constrained condition. This means that it is difficult to find university good algorithm. An optimal path with a complicated computation generates a time delay which cannot avoid moving obstacles. In this paper, we propose an algorithm of path planning and obstacle avoidance for mobile robot. We call the proposed method Random Access Sequence(RAS) method. In the proposed method, a small region is set first and numbers are assigned to its neighbors, then the path is selected using these numbers and cumulative numbers. It has an advantage of fast planning time and completeness of path if one exists. This means that new path selection may be possible within short time and that helps a robot to avoid obstacle in dynamic environments. Using the information of the start and destination position, the RAS can be performed for collision-free navigation by reforming feasible paths repeatedly in dynamic environments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.9
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• pp.1279-1292
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• 2022

This study proposes a non-contact input method based on face recognition and Pyautogui mouse control as a system that can help users who have difficulty using input devices such as conventional mouse due to physical discomfort. This study includes features that help web surfing more conveniently, especially screen zoom, scroll function, and also solves the problem of eye fatigue, which has been suggested as a limitation in existing non-contact input systems. In addition, various set values can be adjusted in consideration of individual physical differences and Internet usage habits. Furthermore, no high-performance CPU or GPU environment is required, and no separate tracker devices or high-performance cameras are required. Through these studies, we intended to contribute to the realization of barrier-free access by increasing the web accessibility of the disabled and the elderly who find it difficult to use web content.