• Journal of Communications and Networks
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• v.17 no.2
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• pp.133-144
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• 2015

In this paper, we introduce a system and a set of algorithms for disseminating popular content to a large group of wireless clients spread over a wide area. This area is partitioned into multiple cells and there is a base station in each cell which is able to broadcast to the clients within its radio coverage. Dissemination of information in the proposed system is hybrid in nature: Each base station broadcasts a fraction of information in the form of random linear combinations of data blocks. Then the clients cooperate by exchanging packets to obtain their desired messages while they are moving arbitrarily over the area. In this paper, fundamental trade-offs between the average information delivery completion time at the clients and different parameters of the system such as bandwidth usage by the base stations, average energy consumption by the clients and the popularity of the spread information are studied. Moreover different heuristic algorithms are proposed to control and maintain a balance over these trade-offs. Also, the more complicated case of multiple sessions where each client is interested in an arbitrary subset of sessions is considered and two variants of the basic dissemination algorithm are proposed. The performance of all the proposed algorithms is evaluated via extensive numerical experiments.

• Plant Biotechnology Reports
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• v.5 no.4
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• pp.301-308
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• 2011

This study tested the relative and combined efficacy of ShPx2 and ShPAL transgenes by comparing Nicotiana tabacum hybrids with enhanced levels of $_L$-phenylalanine ammonia lyase (PAL) activity and cationic peroxidase (Prx) activity with transgenic parental lines that overexpress either transgene. The PAL/Prx hybrids expressed both transgenes driven by the 35S CaMV promoter, and leaf PAL and Prx enzyme activities were similar to those of the relevant transgenic parent and seven- to tenfold higher than nontransgenic controls. Lignin levels in the PAL/Prx hybrids were higher than the PAL parent and nontransgenic controls, but not significantly higher than the Prx parent. All transgenic plants showed increased resistance to the necrotrophs Phytophthora parasitica pv. nicotianae and Cercospora nicotianae compared to nontransgenic controls, with a preponderance of smaller lesion categories produced in Prx-expressing lines. However, the PAL/Prx hybrids showed no significant increase in resistance to either pathogen relative to the Prx parental line. These data indicate that, in tobacco, the PAL and Prx transgenes do not act additively in disease resistance. Stacking with Prx did not prevent a visible growth inhibition from PAL overexpression. Practical use of ShPAL will likely require more sophisticated developmental control, and we conclude that ShPx2 is a preferred candidate for development as a resistance transgene.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.10
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• pp.4957-4976
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• 2016

This paper investigates the error performance of the amplify-and-forward (AF) relaying systems in the context of full-duplex (FD) communication. In addition to the inherent self-interference (SI) due to simultaneous transmission and reception, coexistent FD terminals may cause crosstalk. In this paper, we utilize the information exchange via the crosstalk channel to construct a particular distributed space-time code (DSTC). The residual SI is also considered. Closed-form pairwise error probability (PEP) is first derived. Then we obtain the upper bound of PEP in high transmit power region to provide more insights of diversity and coding gain. The proposed DSTC scheme can attain full cooperative diversity if the variance of SI is not a function of the transmit power. The coding gain can be improved by lengthening the frame and proper power control. Feasibility and efficiency of the proposed DSTC are verified in numerical simulations.

• Journal of Information Processing Systems
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• v.15 no.3
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• pp.604-615
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• 2019

Single-user spectrum sensing is susceptible to multipath effects, shadow effects, hidden terminals and other unfavorable factors, leading to misjudgment of perceived results. In order to increase the detection accuracy and reduce spectrum sensing cost, we propose an adaptive cooperative sensing strategy based on an estimated signal-to-noise ratio (SNR). Which can adaptive select different sensing strategy during the local sensing phase. When the estimated SNR is higher than the selection threshold, adaptive double threshold energy detector (ED) is implemented, otherwise cyclostationary feature detector is performed. Due to the fact that only a better sensing strategy is implemented in a period, the detection accuracy is improved under the condition of low SNR with low complexity. The local sensing node transmits the perceived results through the control channel to the fusion center (FC), and uses voting rule to make the hard decision. Thus the transmission bandwidth is effectively saved. Simulation results show that the proposed scheme can effectively improve the system detection probability, shorten the average sensing time, and has better robustness without largely increasing the costs of sensing system.

• IEMEK Journal of Embedded Systems and Applications
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• v.17 no.6
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• pp.375-382
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• 2022

This paper proposes a multi-core cooperative computing structure considering the heterogeneous features of automotive embedded on-chip software. The automotive embedded software has the heterogeneous execution flow properties for various hardware drives. Software developed with a homogeneous execution flow without considering these properties will incur inefficient overhead due to core latency and load. The proposed method was evaluated on an target board on which a automotive MCU (micro-controller unit) with built-in multi-cores was mounted. We demonstrate an overhead reduction when software including common embedded system tasks, such as ADC sampling, DSP operations, and communication interfaces, are implemented in a heterogeneous execution flow. When we used the proposed method, embedded software was able to take advantage of idle states that occur between heterogeneous tasks to make efficient use of the resources on the board. As a result of the experiments, the power consumption of the board decreased by 42.11% compared to the baseline. Furthermore, the time required to process the same amount of sampling data was reduced by 27.09%. Experimental results validate the efficiency of the proposed multi-core cooperative heterogeneous embedded software execution technique.

• Journal of the Korean Society for information Management
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• v.22 no.1 s.55
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• pp.229-248
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• 2005

This study proposes a national cooperative model of access point control, that enables local systems to utilize national access point control record, without creating their own authority records. In order to applying this model, a client/server system is developed using SRU (Search and Retrieve URL Service) protocol. The suggested access point control system will be a cost-effective and time-saving model for the local system, and will be more flexible and extensible with concept of access point control, XML record format and SRU protocol.

• International Journal of Automotive Technology
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• v.6 no.5
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• pp.545-554
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• 2005

Passive velocity field control (PVFC) was previously developed for fully mechanical systems, in which the motion task was specified by behaviors in terms of a velocity field and the closed-loop was passive with respect to the supply rate given by the environment input. However, the PVFC was only applied to a single manipulator. The proposed control law was derived geometrically and the geometric and robustness properties of the closed-loop system were also analyzed. In this paper, we propose a virtual passivity-based algorithm to apply decentralized control to multiple 3­wheeled mobile robotic systems whose subsystems are under nonholonomic constraints and convey a common rigid object in a horizontal plain. Moreover, it is shown that multiple robot systems ensure stability and the velocities of augmented systems converge to a scaled multiple of each desired velocity field for cooperative mobile robot systems. Finally, the application of proposed virtual passivity-based decentralized algorithm via system augmentation is applied to trace a circle and the simulation results is presented in order to show effectiveness for the decentralized control algorithm proposed in this research.

• Journal of Korean Library and Information Science Society
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• v.54 no.1
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• pp.25-44
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• 2023

This study was to prepare a development plan for nationwide authority control system based on national authority sharing system of NLK through the survey targeting on libraries which do not participate in the system. Six plans were suggested to establish a nationwide authority control system based on this survey. First, an authority data construction module and a module linked to the national authority sharing system should be developed. Second, describing external identifiers such as ISNI to the national authority sharing system is to provides reliability of data and to utilizes to build linked data. Third, it is necessary to prepare strategies for promoting the national authority sharing system and diversifying services. Fourth, both authority establishment and non-establishment show difficulties and diversity in the selection and description of authorized access point, so it is necessary to prepare rules related to authorized access points. Fifth, since the data described in authority records is not enough, it is necessary to improve and upgrade authority records by using bibliographic records. Sixth, it is necessary to educate librarians about the necessity and function of authority control. As such, this study is meaningful in that it investigated the current status and requirements of libraries that do not participate in the nationwide authority system and sought ways to establish a nationwide cooperative authority control system.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.3-10
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• 2012

In this paper, CDD(Cyclic Delay Diversity)-DSF(decode-and-selectively forward) relay schemes are proposed for MC-CDMA(multicarrier-code division multiple access) systems over multipath Rayleigh fading channels. On the contrary to general DSF schemes, each relay equipped a CDD method can transmit on single channel. Therefore, all link channels between destination and relays can be considered as a single channel which is widely delay spread. The cooperative diversity of relay networks can be obtained as the frequency diversity for MC-CDMA systems with proposed CDD schemes. Furthermore, a semi-analytical approach for the averaged bit error rare(BER) performance evaluation is proposed for the proposed CDD-DSF-Relay schemes. By simulation and numerical results, it is confirmed that the proposed one can be a possible solution to achieve cooperative diversity gain without a reduction of spectral efficiency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.8
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• pp.1804-1810
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• 2013

In this paper, we study the opportunistic cooperation scheme that improves the outage performance through the efficient selection between a cooperative mode and a non-cooperative mode. Especially, in decode-and-forward relaying systems, we analyze the outage performance for the opportunistic cooperation using partial relay selection, where closed-form expressions of exact and asymptotic outage probabilities are derived assuming independent and identically distributed Rayleigh fading channels. In the numerical results, we verify the derived expressions, and investigate the outage performances for various target data rates and different numbers of relays. Also, we compare the outage performances of the conventional cooperation scheme and the opportunistic cooperation scheme.