• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.4
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• pp.189-196
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• 2023

As the manufacturing paradigm shifts, various collaborative robots are creating new markets. Demand for collaborative robots is increasing in all industries for the purpose of easy operation, productivity improvement, and replacement of manpower who do simple tasks compared to existing industrial robots. However, accidents frequently occur during work caused by collaborative robots in industrial sites, threatening the safety of workers. In order to construct an industrial site through robots in a human-centered environment, the safety of workers must be guaranteed, and there is a need to develop a collaborative robot guard system that provides reliable communication without the possibility of dispatch. It is necessary to double prevent accidents that occur within the working radius of cobots and reduce the risk of safety accidents through sensors and computer vision. We build a system based on OPC UA, an international protocol for communication with various industrial equipment, and propose a collaborative robot guard system through image analysis using ultrasonic sensors and CNN (Convolution Neural Network). The proposed system evaluates the possibility of robot control in an unsafe situation for a worker.

• The Journal of Korean Philosophical History
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• no.25
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• pp.197-222
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• 2009

In this treatise, the researcher closely examined the I-Xue(易學) compiled and edited by YulGok(栗谷) with a focus on the concept, namely Communication(疏通). I-Xue(易學) compiled by YulGok(栗谷) adopted the discourses of I-Xue(易學) or changes in the Song Dynasty of ancient China, and engrafted his own logics, dubbed Liqizhimiao(理氣之妙), thereunto. In YulGok(栗谷)'s I-Xue(易學), Liqizhimiao(理氣之妙) expresses a state of exchanging information and Communication(疏通), and, at this time, Communication(疏通) encompasses not only the meaning of communication between two heterogeneous factors but also the broader meaning of Communication(疏通) that embrace the Communication(疏通) between heaven and human beings. In his theories in relation to Tiyongyiyuan(體用一源) and Heluoxiangshulun(河洛象數論), YulGok(栗谷) also applied the logic of Communication(疏通). Although YulGok(栗谷) admits the general theory that substance and function have the same source, which understands principle and phenomenon as two forms of existence, he tried to place emphasis more on the aspect of Communication(疏通) by interpreting Li(理) and Xiang(象) in terms of the issues concerned with Li(理) and Jian(踐). In his theory concerned with Magic Squares and Circles, Images and Numbers, such a standpoint is being applied likewise. By emphasizing the fact that Hetu("河圖") may turn out to be Luoshu("洛書"), and vice versa, YulGok(栗谷) stressed that there are communicative relations that are required in order to communicate ideas to one another. In YulGok(栗谷)'s I-Xue(易學), the logic of Communication(疏通) is culminated with the discourse of Tianrenjiaoyu(天人交與). YulGok(栗谷), in his book Ishuce(易數策), uses such expression as Tianrenjiaoyuzhimiao(天人交與之?), and, at this time, he used this expression bearing Liqizhimiao(理氣之妙) in mind. The reason for using the expression, such as Jiaoyu(交與), in lieu of Heyi(合一) is that YulGok(栗谷) tried to emphasize such relations as that heaven and humans are required for interrelated relationship. Tianrenjiaoyu(天人交與) is an expression to indicate the close relationship between heaven and human beings, meanwhile, however, YulGok(栗谷) puts more emphasis on human efforts than those that of heaven. The reason for introducing human as the subjective figure in the Tianrenjiaoyu(天人交與) is that YulGok(栗谷) tried to stress practical efforts of humans.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.9
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• pp.381-392
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• 2013

During the last decade, the multitude of advances attained in terminal computers, along with the introduction of mobile hand-held devices, and the deployment of high speed networks have led to a recent surge of interest in Quality of Service (QoS) for video applications. The main difficulty is that mobile devices experience disparate channel conditions, which results in different rates and patterns of packet loss. One way of making more efficient use of network resources in video services over wireless channels with heterogeneous characteristics to heterogeneous types of mobile device is to use a scalable video coding (SVC). An SVC divides a video stream into a base layer and a single or multiple enhancement layers. We have to ensure that the base layer of the video stream is successfully received and decoded by the subscribers, because it provides the basis for the subsequent decoding of the enhancement layer(s). At the same time, a system should be designed so that the enhancement layer(s) can be successfully decoded by as many users as possible, so that the average QoS is as high as possible. To accommodate these characteristics, we propose an efficient transmission scheme which incorporates SVC-aware dual-channel repetition to improve the perceived quality of services. We repeat the base-layer data over two channels, with different characteristics, to exploit transmission diversity. On the other hand, those channels are utilized to increase the data rate of enhancement layer data. This arrangement reduces service disruption under poor channel conditions by protecting the data that is more important to video decoding. Simulations show that our scheme safeguards the important packets and improves perceived video quality at a mobile device.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.34-47
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• 2018

As interest in advanced countries regarding the convergence technology development increases, a methodology for identifying the core convergence technology that has a large spill-over effect on the technology and industry is required for the nation's competitiveness enhancement in the convergence technology field. Based on patent citation network analysis using 1,124 USPTO patents in the ICT convergence technology field of the smart factory, this study examined the proposed heterogeneous technology convergence index as a tool for measuring the convergence characteristics of the spillovers compared to other indexes (i.e. other sector ratio index and homogeneous technology convergence index). The proposed heterogeneous technology convergence index was used to investigate core technology sectors among ICT technology sectors of smart factory identified by government ministries. Results found 6 core ICT convergence technology sectors including the manufacturing execution analysis application sector. Also, this study conducted blockmodeling analysis using the IPC codes of patents in the manufacturing execution analysis application sector, and identified that the blocks representing the electronic communication and electric digital data processing technology sectors (Block 3 & 4) are related technology sectors which can be converged with core technology. Based on the findings, the implications for the convergence technology development planning of the smart factory field are discussed.

• Journal of Broadcast Engineering
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• v.18 no.2
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• pp.215-224
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• 2013

With the rising popularity of smart-phones, the supply of Internet protocol television is largely increased and it causes the wireless communication network load to be increased. To overcome such an overloading problem, 3GPP is now working on the standardization of MBMS since LTE Release 6 specification. MBMS has good performance in bandwidth efficiency by sharing the same bandwidth with the mulitple MBMS users having the same content. According to the proposed algorithm, in heterogeneous networks having a dispersed Single-cell MBMS where 3GPP network and Wi-Fi network are mixed, if the number of MBMS users, who are belonging to cells supporting a dispersed Single-cell MBMS, is more than a specified threshold, the MBMS priority policy is operated. Otherwise, the Wi-Fi priority policy is executed. As the simulation results show both the increase of total available bandwidth ratio and the decrease of network usage cost, it is confirmed that the proposed scheme allows the network efficiency to be maximized.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5B
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• pp.456-477
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• 2006

Due to advances in wireless communication technology and increasing demand for various types of wireless access, cellular, WLAN, and portable internet(such as WiBro and IEEE 802.16) systems are likely to be integrated into a unified wireless access system. This expectation premises the availability of multi-mode handsets and cooperative interworking of heterogenous wireless access networks allied by roaming contracts. Under such environments, a user may lie in the situation where more than one wireless accesses are available at his/her location, and he/she will want to choose the 'best' access among them. In this paper, we define the 'best' access(es) as the access(es) that charges minimum cost while fulfilling the required QoS of wireless access, and address the problem of choosing the optimal set of accesses theoretically by introducing a graph representation of service environment. Two optimal selection algorithms are proposed, which individually consider cases where single or multiple wireless access can be supported by multi-mode handsets.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.12
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• pp.1814-1823
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• 2016

LVC(live-virtual-constructive) integrated training system is a representative cyber-physical system. Each systems in a LVC system has different time domain, resolution and operation methods. So, it is very important to integrate different middlewares as a common middleware for heterogeneous systems using inter-working GWs. Especially, since the LVC system uses different time, it is necessary to study the method for guaranteeing causality and time synchronization among the events from different systems. In this study, we propose an time synchronization scheme to integrate the virtual and constructive system which use the simulation time of HLA (High Level Architecture)/ RTI (Run Time Infrastructure) into the live system based on the OMG DDS (Data Distribution Service). We propose a precise time synchronization scheme based on HLA time management and clock federate between participants and federates which are the communication objects of DDS and HLA/RTI respectively. In addition, we verified that time is well-synchronized among heterogeneous systems using the suggested scheme by implementing and demonstrating simulation applications on each middleware.

• The Transactions of the Korea Information Processing Society
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• v.7 no.11S
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• pp.3633-3650
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• 2000

Internet is no longer a network for special communities but became a global means of communication infrastructure for everyday life. People are exchanging their personal messages using e-mails, students are getting their educational aids through the web, people are buying a variety of goods from cyber shopping malls, and companies are conducting their businesses over the Internet. Recently, such an explosive growth of the traffic in the Internet raised a big concern on how to accommodate ever-changing user's needs in terms of an amount of the traffic, characteristics of the traffic, and various service quality requirements, Over provisioning can be a simple solution but it is too expensive and inefficient. Thus many new technologies to solve this very difficult puzzle have bcen introduced recently, Any single solution, however, can be insufficient and a carefully designed architecture, which integrates a group of solutions, is required. In this paper, we propose a policy-based Internet QoS provisioning, traffic engineering and perfonnance management system as our solution to this problem. Our integrated management QoS solution can provide highly responsive flow-through service provisioning, more realistic service and resource policy control based on the real network performance information, and centralized control of traffic engineering for heterogeneous networks.

• The Journal of the Korea Contents Association
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• v.10 no.8
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• pp.73-83
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• 2010

This paper investigates protocol architecture of a Web-ZigBee gateway for interconnecting TCP/IP-based networks and ZigBee/IEEE802.15.4-based wireless sensor networks. The Web-ZigBee gateway delivers data between the TCP/IP network and the ZigBee network. Since those two networks have different communication protocols, a protocol translation mechanism is needed. Herein, we propose a method to deliver query messages from the Internet to the sensor network and receive data from sensors. The protocol translation is performed in the translation layer that is placed above the two application layers, i.e., the Internet application layer and ZigBee application layer. Among various interfaces, we use CGI programming to take care of translation functions efficiently. The CGI manages query information from a client on the Internet and data from the ZigBee sensor network. Whereas the TCP/IP enabled sensor network overlays two heterogeneous communication protocols, overlaying layers increase the complexity and cost of implementing the sensor network. On the contrary, the sensors in our gateway-based system are not only light (because each communication protocol works independently without overlaying), but also efficient because the translation layer mostly alleviates header overloading.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.5
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• pp.9-20
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• 2005

In this paper, we propose ubiTrack, a system which tracks users' location in indoor environments by employing infrared-based proximity method. Most of recently developed systems have focussed on performance and accuracy. For this reason, they adopted the idea of centralized management, which gathers all information in a main system to monitor users' location. However, these systems raise privacy concerns in ubiquitous computing environments where tons of sensors are seamlessly embedded into environments. In addition, centralized systems also need high computational power to support multiple users. The proposed ubiTrack is designed as a passive mobile architecture to relax privacy problems. Moreover, ubiTrack utilizes appropriate area as a unit to efficiently track users. To achieve this, ubiTrack overlaps each sensing area by utilizing the TDM (Time-Division Multiplexing) method. Additionally, ubiTrack exploits various filtering methods at each receiver and utilization module. The filtering methods minimize unexpected noise effect caused by external shock or intensity weakness of ID signal at the boundary of sensing area. ubiTrack can be applied not only to location-based applications but also to context-aware applications because of its associated module. This module is a part of middleware to support communication between heterogeneous applications or sensors in ubiquitous computing environments.