• 산업경영시스템학회지
• /
• 제43권1호
• /
• pp.79-86
• /
• 2020

The effects of R&D investment on innovation such as patents and intangible assets, and the effect on the corporate performance such as revenue and profit growth, were analyzed using path analysis. In particular, this study compared and analyzed the performances of non-cooperative R&D and cooperative R&D. The results of this study are summarized as follows. First, R&D investment has a significant impact on innovation performance. This supports the existing research results. Second, patents have a significant impact on intangible asset growth. Third, in the case of corporate groups carrying out cooperative R&D, intangible asset growth forms a significant causal relationship with revenue growth. Fourth, in case of cooperative R&D, intangible asset growth has a significant mediating effect between patent and revenue growth. Like the existing research, the results of this research support the innovation performance of R&D investment. It also supports the existing argument that the results of cooperative R&D are more favorable to increase corporate value. However, unlike the existing research, we found a path leading to increased revenue through patents and intangible assets, and confirmed that such a path is likely to be achieved through cooperative R & D rather than internal R&D.

• Asia pacific journal of information systems
• /
• 제9권1호
• /
• pp.17-38
• /
• 1999

While the value of information technology has long been a hot issue, few solid results have been found as of yet. It is partly due to methodological factors and model underspecifcation. This study empirically develops a ITS(information technology structure) taxonomy and investigates the relationships between ITS taxonomy and business performance in the Korean firms. Among factors that impact business performance, organization structure and control system are selected and they are hypothesized to moderate-the relationships between ITS taxonomy and business performance. By surveying 91 manufacturing firms and applying hierarchical cluster analysis, four ITS are identified : centralized, decentralized, centralized cooperative, decentralized cooperative. ANOVA, correlation analysis and crosstable analysis say the presence of moderating effect of organization structure and control system. Cooperative ITS is best in business performance. Centralized ITS is related to functional organizational form. Decentralized ITS is related to product organizational form with decentralized decision making, Centralized cooperative ITS is related to matrix organizational form. Decentralized cooperative ITS is related to matrix organizational form with high integration. These findings have implications for the opportunities and challenges to match information technology with organization structure and control system.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제6권6호
• /
• pp.1668-1688
• /
• 2012

Cooperative communications and network coding schemes have been proposed to increase system throughput for ad hoc networks. In this paper, we present throughput and delay analysis of the new network coding-enabled cooperative MAC protocol called NC-MAC, which has been proposed by us in order to significantly enhance system performance. This protocol introduces an approach that can accommodate both cooperative communication and network coding for wireless ad hoc networks by slightly increasing overhead and modifying standards. The protocol's performance is evaluated using mathematical analysis and computer simulation and two performance measures, system throughput and average channel access delay, are used for a performance comparison with previous schemes. It is assumed that all the frames exchanged over a wireless channel are susceptible to transmission errors, which is a new but more reasonable assumption differentiating this research from previous research. Numerical results show this protocol provides significantly enhanced system performance compared with conventional cooperative MAC protocols used in previous research. For instance, system performance is 47% higher using the NC-MAC protocol than when using the rDCF protocol.

• International Journal of Internet, Broadcasting and Communication
• /
• 제15권3호
• /
• pp.14-23
• /
• 2023

The cooperative communication systems using MIMO(multiple input multiple-output) relay are known as one of the most promising techniques to improve the performance and coverage of wireless communication systems. In this paper, we propose the cooperative communication systems using the relay with multi-antennas and DSTC(distributed space time coding) for decode-and-forward protocol. As using DSTC for DF(decode-and-forward), we can minimize the risk of error propagation at the wireless system using relay system. Also, the MIMO channel cab be formed by multi-antenna and DSTC at the MS(mobile station)-RS(relay station) and at the RS-BS(base station).Therefore, obtaining truly constructive the MIMO diversity and cooperative diversity gain from the proposed approach, the performance of system can be more improved than one of conventional system (relay with single antenna, no relay). The improvement in bit error rate is investigated through numerical analysis of the cooperative communication system with the proposed approach.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2003년도 ICCAS
• /
• pp.728-733
• /
• 2003

In human-mechanical cooperative systems, a significant issue is to improve the control performance and the maneuvering feeling of human operation. However, since it is not easy to evaluate the feeling of operators numerically, control engineers design controllers only through experience. Thus, in this paper, a new evaluation method for control performance of human-mechanical cooperative system is proposed based on the reserge waveform. Various distortions of waveform represent deteriorations of control performance and maneuvering feeling. In some cases, since there is a tradeoff between the control performance and the maneuvering feeling, it is difficult to compensate for both of them by usual feedback controllers. To overcome this situation, the two degrees of freedom control system is applied to human-mechanical cooperative system. Some numerical simulation results for an electric power steering system are shown to confirm the effectiveness of proposed control design method.

• Journal of Communications and Networks
• /
• 제13권4호
• /
• pp.377-384
• /
• 2011

Cooperative beamforming has previously been proven to be an efficient way to improve the cooperative diversity. This method generally requires all relay nodes to participate in beamforming, which can be seen as "all participate" cooperative beamforming. However, not all relay nodes have constructive impacts on the end-to-end bit error rate (BER) performance. Based on this observation, we propose a new cooperative scheme which only selects those "appropriate" relay nodes to perform cooperative beamforming. Such relay nodes can be simply determined with mean channel gains. Therefore, the selection complexity is significantly reduced as global instantaneous channel state information is not required. This scheme guarantees that energy is only allocated to the "appropriate" relay nodes, and hence provides superior diversity. We also prove that power allocation among source and selected relay nodes is a convex problem, and can be resolved with lower computational complexity. Simulation results demonstrate that our scheme achieves an essential improvement in terms of BER performance for both optimal and limited feedback scenarios, as well as high energy-efficiency for the energy-constrained networks.

• 디지털융복합연구
• /
• 제12권4호
• /
• pp.133-143
• /
• 2014

본 연구는 거래비용요소가 경영성과에 미치는 영향을 검증한 것이다. 연구결과, 첫째, 불확실성은 재무적 성과와 비재무적성과에 직접적으로 영향을 미치는 것으로 나타났지만, 자산특유성과 기회주의는 경영성과에 직접적인 영향이 없는 것으로 분석되었다. 둘째, 협력관계 지속요인에 직접적으로 영향을 미치는 변수는 자산특유성과 불확실성으로 나타났으나. 기회주의는 직접적인 영향이 없는 것으로 나타났다. 셋째, 관계만족도에 직접적으로 영향을 미치는 변수는 자산특유성과 기회주의로 나타났으며, 불확실성과의 관계는 없는 것으로 분석됐다. 넷째, 협력관계 지속요인과 관계만족도는 재무적 성과와 비재무성과에 각각 직접적으로 영향을 미치는 것으로 나타났다. 요약하면, 거래비용요소가 협력관계 지속요인과 관계만족도라는 매개변수를 통하여 경영성과에 영향을 미치고 있음을 발견하였다.

• Journal of Communications and Networks
• /
• 제10권2호
• /
• pp.163-174
• /
• 2008

Performance of downlink transmission strategies exploiting cooperative transmit diversity is investigated for distributed multiple-input single-output (MISO) systems, for which geographically distributed remote antennas (RA) in a cell can either communicate with distinct mobile stations (MS) or cooperate for a common MS. Statistical characteristics in terms of the signal-to-interference-plus-noise ratio (SINR) and the achievable capacity are analyzed for both cooperative and non-cooperative transmission schemes, and the preferred mode of operation for given channel conditions is presented using the analysis result. In particular, we determine an exact amount of the maximum achievable gain in capacity when RAs for signal transmission are selected based on the instantaneous channel condition, by deriving a general expression for the SINR of such antenna selection based transmission. For important special cases of selecting a single RA for non-cooperative transmission and selecting two RAs for cooperative transmission among three RAs surrounding the MS, closed-form formulas are presented for the SINR and capacity distributions.

• 한국통신학회논문지
• /
• 제34권2A호
• /
• pp.124-131
• /
• 2009

Cognitive radio has been proposed to mitigate the spectrum scarcity problem by allowing the secondary users to access the under-utilized frequency bands and opportunistically transmit. Spectrum sensing, as a key technology in cognitive radio, is required to reliably detect the presence of primary users to avoid the harmful interference. However, it would be very hard to reliably detect the presence of primary users due to the channel fading, shadowing. In this paper, we proposed a distributed cooperative spectrum sensing scheme based on conventional DF (decode-and-forward) cooperative diversity protocol. We fist consider the cooperation between two secondary users to illustrate that cooperation among secondary users can obviously increase the detection performance. We then compare the performance of DF based scheme with another conventional AF (amplify-and-forward) protocol based scheme. And it is found that the proposed scheme based on DF has a better detection performance than the one based on AF. After that, we extend the number of cooperative secondary users, and demonstrate that increasing the cooperation number can significantly improve the detection performance.

• 한국인터넷방송통신학회논문지
• /
• 제12권4호
• /
• pp.31-36
• /
• 2012

본 논문에서는 인지무선통신에서 중요한 기술 중 하나인 스펙트럼 센싱의 Hidden node의 문제나 셀룰라 시스템에서 셀 경계에서 CPE(Customer Premises equipments)의 낮은 SNR(Signal to Noise Ratio)로 인한 센싱 성능 저하를 해결하기 위해 CPE들의 협력 릴레이 기법을 사용한 협력 스펙트럼 센싱을 제안하고 검출확률 성능을 분석한다. 송신단과 수신단 사이의 릴레이(Relay) 적용된 협력 스펙트럼 센싱은 가상의 공간 다이버시티이득(Spatial Diversity Gain)을 얻을 수 있어 센싱 성능이 향상된다. 협력 통신 기법 중 다중안테나를 적용한 AF(Amplify and Forward) 고정형 중계기를 사용하여 다이버시티이득을 얻는 시스템 모델을 제안하고, 검출 성능 향상을 분석한다.