• ETRI Journal
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• v.38 no.6
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• pp.1042-1051
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• 2016

The mobile hotspot network (MHN), which is capable of providing a data rate of gigabits per second at high speed, is considered a potential use case of the future enhanced mobile broadband for 5G. Because a unidirectional network deployment has been considered for an MHN, non-orthogonal multiple access (NOMA) can be employed to improve the system performance. For a practical implementation of NOMA under an MHN highway scenario where multiple pieces of MHN terminal equipment are served through the same beam simultaneously, a NOMA transceiver is proposed in this paper. For the NOMA transmitter, Gray-coded QAM constellation mapping is extended to arbitrary modulation order q. For the NOMA receiver, successive interference cancellation (SIC) is no longer necessary, and instead, a parallel demodulation is proposed. The numerical and simulation results suggest that the proposed NOMA transceiver outperforms the conventional NOMA SIC receiver and can be flexibly used for an MHN highway scenario.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.325-326
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• 2006

Using $6wt%Y_2O_3-2wt%Al_2O_3$ as sintering additives and Si as a raw powder, the continuously porous in-situ $Si_2N_2O-Si_3N_4$ bodies were fabricated by multi-pass extrusion process and their microstructures were investigated depending on the addition of carbon (0-9wt%) in the mixture powder. The introduction of $Si_2N_2O$ fibers observed in the unidirectional continuous pores as well as in the pore-frame regions of the nitrided bodies can be an effective method in increasing the filtration efficiency. In the case of no carbon addition, the network type $Si_2N_2O$ fibers with high aspect ratio appeared in the continuous pores with diameters of 150-200 nm. However, in the case of 9wt% C addition, the fibers were found without any network type and had diameters of 200-250 nm.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.5
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• pp.1295-1304
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• 2016

Commercial Off The Shelf(COTS) based one-way communication is advantageous in that support a low cost communication and high speed one-way communication. This paper introduce a one-way communication method, and provides a implementation method of one-way communication through modified device driver for COTS NIC. Then, To verify the advantage of the COTS based one-way communication method, We present a sample implementation using Intel 82580 NIC, and present a possibility that can contribute to the realization of one-way communication through experiments on performance and reliability.

• Journal of Biomedical Engineering Research
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• v.9 no.2
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• pp.247-250
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• 1988

Laboratory information system (LIS) is a key tool to manage laboratory data in clinical pathology. Our department has developed an information system for routine hematology using down-sized computer system. We have used an IBM 486 compatible PC with 16MB main memory, 210 MB hard disk drive, 9 RS-232C port and 24 pin dot printer. The operating system and database management system were SCO UNIX and SCO foxbase, respectively. For program development, we used Xbase language provided by SCO foxbase. The C language was used for interface purpose. To make the system use friendly, pull-down menu was used. The system connected to our hospital information system via application program interface (API), so the information related to patient and request details is automatically transmitted to our computer. Our system interfaced with fwd complete blood count analyzers(Sysmex NE-8000 and Coulter STKS) for unidirectional data tansmission from analyzer to computer. The authors suggests that this system based on down-sized computer could provide a progressive approach to total LIS based on local area network, and the implemented system could serve as a model for other hospital's LIS for routine hematology.

• Journal of Communications and Networks
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• v.7 no.4
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• pp.429-437
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• 2005

Sensor localization has become an essential requirement for realistic applications over wireless sensor networks (WSN). In this paper we propose an ad hoc localization algorithm that is infrastructure-free, anchor-free, and computationally efficient with reduced communication. A novel combination of distance and direction estimation technique is introduced to detect and estimate ranges between neighbors. Using this information we construct unidirectional coordinate systems to avoid the reflection ambiguity. We then compute node positions using a transformation matrix [T], which reduces the computational complexity of the localization algorithm while computing positions relative to the fixed coordinate system. Simulation results have shown that at a node degree of 9 we get $90\%$ localization with $20\%$ average localization error without using any error refining schemes.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.525-526
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• 2007

Recently, there has been growing interest in utilizing distributed generation (DG). However, an insertion of DG to existing distribution system can cause several problems such as voltage variations, harmonics, protective coordination, increasing fault current etc,. The typical protection system of the existing distribution system is designed for radial network. But penetration of DG to distribution system changes existing unidirectional power flow to bidirectional power flow. Therefore, investigation to cover whole field of distribution system must be accomplished such as changing of protection devices rating by increasing fault current, reevaluation of protective coordination. This paper presents that PSCAD/EMTDC simulations was accomplished to analyze effect of DG on the distribution protective coordination. In addition, directional recloser-sectionalizer coordination are evaluates distribution system with DG by using PSCAD/EMTDC simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.3
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• pp.310-317
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• 1993

This paper presents a mechanism for improving performance of the IEEE 802.6 MAN(Metropolitan Area Network), a dual-bus structured high-speed communication network, by a more efficient use of bandwidth. The MAN protocol is able to handle various traffic and offers better transmission speed than the conventional LAN, but the unidirectional bus structure and propagation delay of request bits results in unfairness since higher nodes use more bandwidth. As the number of stations and the distances between them are increased, the problem becomes mere serious. As a solution, this paper presents a method that every station enables to identify the used slots, and that a specified class denoted 'erasure station' has with the functions of destination release, slot reuse. As a result, it is export to improve network bandwidth values of each station and the throughput and delay time was analytically analyzed, and it is shown that according to computer simulation results, this mechanism improves the network performance.

• Journal of Korean Academy of Nursing
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• v.52 no.2
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• pp.202-213
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• 2022

Purpose: This study examined characteristics and patterns of interorganizational networks for smoking prevention and cessation in Korea. Methods: We surveyed two community health centers, ninety-five hospitals or clinics, ninety- two pharmacies, and sixty-five health welfare organizations in two districts of Seoul in 2020. Data on the organizations' characteristics of smoking cessation and interorganizational activities for information sharing, client referral, and program collaboration were collected and analyzed using network statistics and blockmodeling. Results: Network size was in the order of information sharing, client referral, and program collaboration networks. Network patterns for interorganizational activities on information sharing, client referral, and program collaboration among four organizations were similar between the two districts. Community health centers provided information and received clients from a majority of the organizations. Their interactions were not unidirectional but mutual with other organizations. Pharmacies were involved in information sharing with health welfare organizations and client referrals to hospitals or clinics. Health welfare organizations were primarily connected with the community health centers for client referrals and program collaboration. Conclusion: A community health center is the lead agency in interorganizational activities for smoking prevention and cessation. However, hospitals or clinics, pharmacies, and health welfare organizations also participate in interorganizational networks for smoking prevention and cessation with diverse roles. This study would be evidence for developing future interorganizational networks for smoking prevention and cessation.

• The KIPS Transactions:PartA
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• v.12A no.6 s.96
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• pp.557-562
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• 2005

Throughput and latency of interconnection network are important factors of the performance of multiprocessor systems. The dual-link CC-NUMA architecture using point-to-point unidirectional link is one of the popular structures in high-end commercial systems. In terms of optimal path between nodes, several paths exist with the optimal hop count by its native multi-path structure. Furthermore, transaction latency between nodes is affected by congestion of links on the transaction path. Hence the transaction latency may get worse if the transactions make a hot spot on some links. In this paper, I propose a dynamic transaction routing algorithm that maintains the balanced link utilization with the optimal path length, and I compare the performance with the fixed path method on the dual-link CC-NUMA systems. By the proposed method, the link competition is alleviated by the real-time path selection, and consequently, dynamic transaction algorithm shows a better performance. The program-driven simulation results show $1{\~}10\%$ improved fluctuation of link utilization, $1{\~}3\%$ enhanced acquirement of link, and $1{\~}6\%$ improved system performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.1B
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• pp.16-23
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• 2009

This paper investigates how many optimal routes can be established in terms of a given wireless mesh routing metric. Although many of routing metrics have been devised to precisely derive the wireless link quality in mesh, most (if not all) metrics have not been evaluated their optimality along with routing protocols. We consider stateof-the-art routing metrics and a widely accepted routing protocol in order to observe the optimality of established routes varying the number of source nodes. Also, we propose a unidirectional routing to deal with possible link asymmetry feature in wireless links. Through comparative simulation evaluations, we show that the portion of optimally established routes becomes less as the network traffic load increases, regardless of employed metrics, network topologies, and routing protocols.