Byung-Ho Rhee

Bio: Byung-Ho Rhee is an academic researcher from Hanyang University. The author has contributed to research in topics: Handover & Equal-cost multi-path routing. The author has an hindex of 3, co-authored 10 publications receiving 26 citations.

Characterization of Performance of a Mobile MIMO Antenna in Free Space

Abstract: This letter presents an antenna design method for a dual antenna with high isolation for mobile stations (MSs) and includes a verification method for improving the correlation performance of an MS that uses a proposed multiple-input-multiple-output (MIMO) antenna by using MIMO over-the-air (OTA) channel models. The large-scale parameters for the MIMO OTA channel models are important because they determine the fixed geometrical parameters to be used for channel impulse response realization. The correlation performance of an MS has a strong relation to the cross-polarization discrimination (XPD) of the second branch antenna both numerically and experimentally. This study applies modern technology to implement MIMO antenna switch high isolation by selecting Band 5 to have low-frequency fabricated antenna samples that have several XPD values, thereby comparing their characteristics.

Knowledge Transfer Activation Analysis: Knowledge Trade Perspective

Abstract: This article empirically analyzes a model of knowledge transfer activation based on trade in knowledge market perspective. We aim to provide insights into trade in the knowledge market through an empirical analysis. Using a research model with a theoretical basis on knowledge sharing culture and trade in knowledge market, we conducted an empirical study using data on enterprises' knowledge management systems (KMSs). The results revealed that 62.6% of the variance in knowledge transfer activation was explained by the items of knowledge organization, knowledge strategy, KMS, and knowledge reward through knowledge sharing culture and trade in knowledge market. This suggests that horizontal organization and a strategy that pursues an organization's objectives positively impact knowledge sharing culture, while knowledge technology (KMS) and reward positively affect the trade in knowledge market. We therefore conclude that trade in knowledge market is an important factor to activate knowledge transfer. This art...

Enhancement of mSCTP mobility scheme for seamless vertical handover

Abstract: In recent years, the requirement for the vertical handover between heterogeneous networks in the wireless communication environments has been steadily increased, as well as the mobility has came into the limelight as one of major issues in the future IP networks [8]. To successfully satisfy this requirement, a solution to apply SCTP [1] which had been proposed in existing transport layer to the wireless networks has been in now progress and also mSCTP to which the function of Dynamic Address Reconfiguration [2] was added was proposed. However, it has been known that this solution didn't show a certain solution for the problem of handover latency time as well as the packet loss caused by the handover and still has a shortcoming of only supporting the mobility. In this paper, we would like to propose a solution that will not require additional network elements using MIH but also, comparing to existing mSCTP, reduce the handover latency time and minimize the network load.

A New HVHD Model Four-Layer Channel Router Using a Channel-Graph.

Abstract: This paper proposes a new HVHD four-channel routing technique using the channel-graph. The diagonal routing model, which differs from the conventional four-layer channel routing, is introduced in the proposed method; and the nets for the diagonal routing are selected by the algorithm based on the weighted channel-graph. The rest net, left after the diagonal routing, is routed in HVH three-layers. The proposed method is applied experimentally to several benchmark data, including Deutsch's difficult example. It is shown that tracks are reduced by approximately 20 percent compared to the conventional four-channel routing method, and the result by the proposed method is closer to the result of the conventional five-layer routing. Thus, the effectiveness of the proposed method based on the channel-graph is demonstrated.

A Study of Knowledge Management System Activation Methods Based on Knowledge Market Theory

Abstract: An importance of knowledge management (KM) leads many companies to utilize knowledge management system (KMS) but the users do not make use of KMS frequently. The purpose of our work is to examine how knowledge market-based price mechanism affects the utilization of current KMS and to find out solutions to improve KMS use. For the purposes of this investigation, we analyzed large enterprises and public institutions using KMS in Korea with differentiated groups by the survey. As a result of the analysis, most companies have operated the KMS relying on traditional KM methodology. It is important to develop appropriate knowledge market-based KMS. In this paper, we presented the future of the market-based system by comparing knowledge market-based KMS with traditional KMS. For the future work, it is recommended that knowledge market-based mechanisms be examined with qualitative research.

High-Isolated MIMO Antenna Design Based on Pattern Diversity for 5G Mobile Terminals

Abstract: In this letter, a novel multiple-input–multiple-output (MIMO) antenna operating at 3500 MHz band is presented for 5G mobile terminals. The proposed antenna includes four blocks. Each block consists of two face-to-face elements with total size of 25 × 3.5 mm2. Rather than excited separately, the two elements are excited simultaneously. Pattern diversity is achieved by using in-phase and out-of-phase signals. A compact two-port feed network is designed to provide the required feed signals. The measured bandwidth for the two ports is 750 MHz (3.06–3.81 GHz) and 340 MHz (3.33–3.67 GHz), which is sufficient to cover the 3400–3600 MHz band. The port isolation is higher than 14 dB in the overlapping bandwidth.

Tightly Arranged Four-Element MIMO Antennas for 5G Mobile Terminals

Abstract: In this paper, a compact multiple-input multiple-output (MIMO) antenna is presented for 5G mobile terminals. The antenna consists of four tightly arranged elements and three lumped components. The edge-to-edge distance between adjacent elements is only 1 mm. It is found that adding an inductor at the current minimum location or a capacitor at the current maximum location of two elements can significantly reduce the mutual coupling. Based on high-isolated dual-element structures, a four-element MIMO antenna is experimentally analyzed for 3400–3600 MHz band. The size of the antenna is only $40.8 \times 3$ mm2. The measured −6 dB bandwidth of the antenna is 135 MHz, with port isolation higher than 11.6 dB. In addition, a vertically placed four-element MIMO antenna is designed with a size of $38.2\times3.2$ mm2. No ground clearance is needed between the antenna and the chassis ground.

Isolation-Improved Dual-Band MIMO Antenna Array for LTE/WiMAX Mobile Terminals

Abstract: A compact dual-band multiple-input–multiple-output (MIMO) antenna array with eight elements is proposed for the Long Term Evolution (LTE)/Worldwide Interoperability for Microwave Access (WiMAX) mobile applications. The dual-band MIMO array consists of four U-slit etched planar inverse-F antennas (PIFAs) and four L-slit etched PIFAs. The two types of PIFAs are placed orthogonally to reduce mutual coupling between them. With the presented decoupling methods in the design including the disconnection of ground plane, the parasitic resonant strips, and also the modified PIFAs, the excellent element isolation (above 20 dB) and other good MIMO performance are achieved. The overall dimension of the MIMO system is only 140 $\,\times\,$ 70 $\, \times\,$ 9.55 mm $^{3}$ , and good return loss (above 10 dB) is achieved across the operating bands (2.6–2.8 and 3.4–3.6 GHz) for all the PIFA elements. The radiation patterns and envelope correlation coefficient (ECC) of MIMO system are also studied, showing quasi-omnidirectional radiation and accepted envelope correlation coefficient across the dual-band operation for mobile communications.

Inner tapered tree-shaped fractal antenna for UWB applications

Abstract: In this article, a compact third iteration inner tapered tree-shaped fractal antenna for ultrawideband applications is presented. The bandwidth is enhanced by using CPW ground plane and increasing the number of iterations. An impedance bandwidth of 4.3–15.5 GHz (113%) is achieved. The proposed third iteration antenna has nearly omnidirectional patterns at its resonance frequencies with an acceptable value of gain. The experimental and simulation results are found to be in good agreement. The proposed antenna has improved return loss performance and miniaturized size. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:559–567, 2015

Benchmarking knowledge management practices in small and medium enterprises: A fuzzy multicriteria group decision-making approach

Abstract: Purpose The purpose of this paper is to formulate the process of measuring and benchmarking the performance of knowledge management (KM) practices as a multicriteria group decision-making problem and present a new multicriteria group decision-making approach for effectively evaluating the performance of KM practices to meet the interests of various stakeholders in small and medium enterprises (SMEs) Design/methodology/approach A new multicriteria group decision-making approach is developed for evaluating the performance of KM practices of individual SMEs Intuitionistic fuzzy numbers are used for representing the subjective assessments of decision makers in evaluating the relative importance of the evaluation criteria and the performance of individual KM practices with respect to specific evaluation criteria A fuzzy multicriteria group decision-making algorithm is developed for measuring and benchmarking the performance of alternative KM practices Findings The proposed multicriteria group decision-making approach is capable of effectively evaluating the performance of KM practices through adequately considering the presence of multiple decision makers, the multi-dimensional nature of the evaluation problem, and appropriately modeling the subjectiveness and imprecision of the evaluation process The presentation of an example shows that the proposed fuzzy multicriteria group decision-making algorithm is simple to use and efficient in computation Research limitations/implications The outcome of the multicriteria group decision-making approach is highly dependent on the inputs provided by the decision maker Practical implications The novelty from this research lies in the utilization of a multicriteria group decision-making approach for evaluating the performance of KM practices in an organization The outcome from the performance evaluation process allows the enterprise to adopt appropriate KM practices for achieving competitive advantages Social implications The proposed multicriteria group decision-making approach has a significant social implication as it can be used as a decision-making tool for providing various decision makers in SMEs with useful and strategic information concerning the performance of KM practices in a given situation Originality/value The originality of this paper lies in the development of the multicriteria group decision-making approach for effectively measuring and benchmarking the performance of KM practices of individual SMEs