• Korean Journal of Optics and Photonics
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• v.30 no.6
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• pp.230-236
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• 2019

We propose and demonstrate a searching and autoalignment method for indoor optical wireless communication, using a cost-effective retroreflective sheet and a microelectromechanical system (MEMS) mirror. We use an extremum-seeking method for a single axis and beam steering with a MEMS mirror to maintain a line of sight (LOS) with the optical link. This autoalignment method shows a receiver sensitivity of -31.87 dBm for a bit rate of 2.5 Gb/s over a 7 m communication link.

• Korean Institute of Interior Design Journal
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• v.16 no.3 s.62
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• pp.21-29
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• 2007

The communication in a play has a dual structure, which is composed of the communications within a play and in a theatre space. This research focuses on the scene design that creates the background or the theme of a play and communicates theme of a play to the audience. A scene design of a theatre has meta-linguistic aspects, which is the image or mood as the theme of a play. The scene design is composed of various design elements of space and objects as the properties of a play. Design elements and the objects are the design languages in various form; plane, three-dimensional, multi-dimensional form. These design languages have the significant meanings as signs like human language. The play works chooses the rhetorical expression to arouse the audience's sympathy. The scene design is completed with rhetorical expression for communication in theatre too. This research defines the category of meanings that design elements of scene design can create and the rhetorical expression of the scene design language. King Lear directed by Robert G. Anderson was analyzed with the category of design elements as a sign and the pattern of the rhetorical expression. The scene design for a play is completed effectively by the rhetorical expression of design elements as the design language for the communication with the audience in theatre.

• ETRI Journal
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• v.42 no.5
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• pp.700-711
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• 2020

Because of the rapid increase of mobile traffic, flexible broadband supportive unmanned aerial vehicle (UAV)-based 6G mobile networks using free space optical (FSO) links have been recently proposed. Considering the advancements made in UAVs, big data processing, and artificial intelligence precision control technologies, the formation of an additional wireless network based on UAV aerial platforms to assist the existing fixed base stations of the mobile radio access network is considered a highly viable option in the near future. In this paper, a combined time bound optimization scheme is proposed that can adaptively satisfy the control and communication time constraints as well as the processing time constraints in FSO-based 6G UAV aerial networks. The proposed scheme controls the relation between the number of data flows, input data rate, number of worker nodes considering the time bounds, and the errors that occur during communication and data processing. The simulation results show that the proposed scheme is very effective in satisfying the time constraints for UAV control and radio access network services, even when errors in communication and data processing may occur.

• Current Optics and Photonics
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• v.5 no.2
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• pp.114-120
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• 2021

Free-space optical (FSO) communication is considered to be a potential solution to congestion in the radio-frequency spectrum and last-mile-access bottleneck issues in future cellular communication networks, such as 5G and beyond. However, FSO link performance may degrade significantly due to irradiance fluctuations and random temporal fluctuations from atmospheric turbulence. Therefore, in this work the main objective is to reduce the effect of the atmospheric turbulence by considering a multihop FSO communication system with amplify-and-forward relaying supported by a radio-frequency (RF) link, which form a hybrid FSO/RF communication system. The FSO link is assumed to follow the gamma-gamma fading model, which represents strong turbulence. Also, the RF link is modeled by a Rayleigh distribution. The performance of the considered system, in terms of the outage probability and average bit-error rate (BER), is investigated and analyzed under various weather conditions and pointing errors. Furthermore, the effect of the number of employed relay nodes on the performance of the system is investigated. The results indicate that the considered system reduces outage probability and average BER significantly, especially for low channel quality. Finally, the closed-form expressions derived in this work are compared to the results of Monte Carlo simulations, for verification.

• Smart Structures and Systems
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• v.30 no.5
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• pp.433-446
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• 2022

Despite efforts to reduce unexpected accidents at confined construction sites, choking accidents continue to occur. Because of the poorly ventilated atmosphere, particularly in long, confined underground spaces, workers are subject to dangerous working conditions despite the use of artificial ventilation. Moreover, the traditional monitoring methods of using portable gas detectors place safety inspectors in direct contact with hazardous conditions. In this study, a long-range (LoRa)-based wireless safety monitoring system that features the network organization, fault-tolerant, power management, and a graphical user interface (GUI) was developed for underground construction sites. The LoRa wireless data communication system was adopted to detect hazardous gases and oxygen deficiency within a confined underground space with adjustable communication range and low power consumption. Fault tolerance based on the mapping information of the entire wireless sensor network was particularly implemented to ensure the reliable operation of the monitoring system. Moreover, a sleep mode was implemented for the efficient power management. The GUI was also developed to control the entire safety-monitoring system and to manage the measured data. The developed safety-monitoring system was validated in an indoor testing and at two full-scale water pipeline construction sites.

• Korean Institute of Interior Design Journal
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• v.20 no.6
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• pp.236-243
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• 2011

The digital space color of new media environment denied not only the deterministic relationship of designed color and circumjacent color but also the deduced an special elements of digital space color. Such phenomena historical perspective of Gernot Wersig, new media principle of Lev Manovich and remediation of Bolter, J.K & Grusin, R. are expressed in various new media environment across. In particular, development of digital technology is moving away from its previous space color based on scientific, statistical and quantitative perspective by using diverse variables. The following research focuses on the fundamental concept of space color by type, composition of digital space color. The paper reflects on the meaning and concept of contemporary which enables the application of digital space color system on space through advanced technology. The principle of digital space color such as multidimensional malerisch, discontinuous video, vague original and copy, irregular repetitiveness of 'copy of copy', selective color of observer, experiential color of observer, and etc. makes it possible to extract the expressed element and method of digital space color. Meanwhile, the features of digital space color such as divided field of form, non-systematized of process and collage of communication can be inferred from case analysis.

• Korean Institute of Interior Design Journal
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• v.25 no.1
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• pp.172-180
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• 2016

This study aimed to evaluate how universal design principles are embodied in the Public Service Center. It will be used for planning the basic materials of the interior environmental design for Public Service Center facilities and for developing ways to improve interior environments in order for them to be conveniently used. In studying a method, we conducted an Universal Design check list to evaluate interior environment, targeting five Public Service Center facilities located in Gwangju Metropolitan city. This study investigated the Universal Design suitability of center interior Public Service Center on the basis of the tools for Universal Design check list which was composed of supportive design, adaptable design, communicability, safety-oriented design, and accessible design. Through theoretically considering the services of Gwangju's old city hall public service center, which got divided into common space, public service space, waiting space and informative material space. Evaluation on universal design application level showed that those with best universal design application are supportiveness and safety in public service space, communication efficacy and safety in waiting space and safety and accessibility in informative material space and acceptability in waiting space had the lowest application level.

• Korean Institute of Interior Design Journal
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• no.13
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• pp.3-10
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• 1997

The purpose of this study was to identify the design concepts embedded in our traditional interior space. The majority of this research was achieved through literature review as well as examining traditional Korean houses. The major findings were summarized as follows : First, traditional Korean interior space is contemplative. This is created possible by the careful placement of indispensable furnitures and accessaries resulting in an abundance of unoccupied space. Therefore, the room assumes a peaceful atmosphere which calms the mind and creates a tranquil setting. To enjoy the placidity of Korean interior space a humble demeanor and contemplative thought are required. Next, traditional Korean interior space is modest. This is created by the moderate proportions that do not challenge human scale. Traditional Korean interior space does not dominate its surroundings but rather conforms with them. This contrasts with traditional western houses which utilizes an overbearing scale sacrificing intimate space. Thirdly, traditional Korean interior space is raw. In other words, the materials used in house retain their self-evident natural state and are not artifically manipulated to hide their inherent properties. The fundamental conceptual belief that interior space should not defy nature but instead become part of it. Lastly, traditional Korean interior space is not decorative Rooms are not congested with frivolous aesthetics. Although this does not immediately attract the people's attention, eventually the interior space establishes a unique line of communication with them.

• Korean Institute of Interior Design Journal
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• v.22 no.5
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• pp.199-206
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• 2013

Design is one of diverse human communication activities. Development of technologies has led to execution of more active design communication functions, stirring social and cultural changes. The concept of design communication has become stronger by overcoming the limitations of verbal communication and expanding the methods of communication. These social changes are highlighted In the design of modern space. Even though communication in interior design activities is so important, detailed studies on communication of each entity are still very insufficient. Design communication refers to tools and activities for overall communications in the design process. In design activities, relevant communication is indispensible. Therefore, studies on practical communication methods are essential for accurate communication of content that has to be shared in the results or in the process of obtaining the results, rather than only focusing on the future techniques and functions of design. In other words, improving the efficiency of interior design communication requires establishing a communication relationship structure of each entity, which calls for proper expression methods depending on each entity. Therefore, this study is aimed at exploring efficient expression methods in line with the relationship structure of each entity in the interior design process.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.5
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• pp.895-901
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• 2016

The next generation wireless and satellite communications require high transmission efficiency and high reliability to provide various services with subscribers. To satisfied these requirements, incorporated MIMO (Multiple Input Multiple Output) system with FTN (Faster Than Nyquist) techniques based on layered space time coded method are considered in the paper. To improve performance, STTC (Space Time Trellis Code) was employed as an inner code. As the same as SISO (Single Input Single Output) system, the outer codes are turbo codes. In receiver side, BCJR algorithm is used for STTC decoding in order to eliminate interferences induced by FTN transmission. They can yield significantly increased the data rates and improved link reliability without additional bandwidth. Therefore, we proposed a new decoding model for MIMO FTN model and confirmed that performance was improved compared to conventional SISO model according to amount of interference for FTN.