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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Journal of Korean Institute of Communications and Information Sciences
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The Korean Institute of Communications and Information Sciences
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Volume & Issues
Volume 41, Issue 8 - Aug 2016
Volume 41, Issue 7 - Jul 2016
Volume 41, Issue 6 - Jun 2016
Volume 41, Issue 5 - May 2016
Volume 41, Issue 4 - Apr 2016
Volume 41, Issue 3 - Mar 2016
Volume 41, Issue 2 - Feb 2016
Volume 41, Issue 1 - Jan 2016
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Two Types of Algorithms for Finding the Cube Root in Finite Fields
Cho, Gook Hwa ;
The Journal of Korean Institute of Communications and Information Sciences, volume 41, issue 5, 2016, Pages 499~503
DOI : 10.7840/kics.2016.41.5.499
We study algorithms that can efficiently find cube roots by modifying Cipolla-Lehmer algorithm. In this paper, we present two type algorithms for finding cube roots in finite field, which improves Cipolla-Lehmer algorithm. If the number of multiplications of two type algorithms has a little bit of a difference, then it is more efficient algorithm which have less storage variables.
A Study on Turbo Equalization for MIMO Systems Based on LDPC Codes
Baek, Chang-Uk ; Jung, Ji-Won ;
The Journal of Korean Institute of Communications and Information Sciences, volume 41, issue 5, 2016, Pages 504~511
DOI : 10.7840/kics.2016.41.5.504
In this paper, MIMO system based on turbo equalization techniques which LDPC codes were outer code and space time trellis codes (STTC) were employed as an inner code are studied. LDPC decoder and STTC decoder are connected through the interleaving and de-interleaving that updates each other`s information repeatedly. In conventional turbo equalization of MIMO system, BCJR decoder which decodes STTC coded bits required two-bit wise decoding processing. Therefore duo-binary turbo codes are optimal for MIMO system combined with STTC codes. However a LDPC decoder requires bit unit processing, because LDPC codes can`t be applied to these system. Therefore this paper proposed turbo equalization for MIMO system based on LDPC codes combined with STTC codes. By the simulation results, we confirmed performance of proposed turbo equalization model was improved about 0.6dB than that of conventional LDPC codes.
Analysis on Spectrum Utilization Strategies in Cognitive Radio Network Based on Multi-Antenna Wireless Energy Transfer
Lee, Sung-bok ; Park, Jaehyun ; Kang, Kyu-Min ; Park, Yunju ;
The Journal of Korean Institute of Communications and Information Sciences, volume 41, issue 5, 2016, Pages 512~519
DOI : 10.7840/kics.2016.41.5.512
This paper presents spectrum utilization strategies in cognitive radio (CR) networks powered by multi-antenna based wireless energy transfer. Secondary access point (AP) with multiple antennas should transfer the energy to the secondary sensor nodes with energy beamforming and simultaneously induces no interference to PUs. In addition, sensor nodes can transmit information to the secondary AP using the harvested energy, only when the spectrum is not utilized by PUs. We analyze the achievable rate of the CR sensor networks and propose an interference nulling energy beamforming method to maximize the achievable rate. Finally, we also propose a frame scheduling algorithm in which the durations of wireless energy transfer/information transfer frames (phases) are optimized.
Beamforming Based CSI Reference Signal Transmission for FDD Massive MIMO Systems
Hong, Jun-Ki ; Jo, Han-Shin ; Mun, Cheol ; Yook, Jong-Gwan ;
The Journal of Korean Institute of Communications and Information Sciences, volume 41, issue 5, 2016, Pages 520~530
DOI : 10.7840/kics.2016.41.5.520
Since FDD massive MIMO (multiple-input multiple-output) system deploys hundreds of transmit antennas at base station (BS) compared to conventional MIMO system, the overhead of transmitting channel state information reference signal (CSI-RS) increases proportionally to the number of transmit-antennas. To overcome these disadvantages, we proposed beamforming based CSI-RS transmission technique for FDD massive MIMO system which transmit CSI-RS by limited amount of downlink resources.
Performance Evaluation and Analysis of MIMO-IBFD Systems
An, Changyoung ; Kung, Kyung-Lok ; Kim, Byeongjae ; Ryu, Heung-Gyoon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 41, issue 5, 2016, Pages 531~538
DOI : 10.7840/kics.2016.41.5.531
In this paper, we have proposed MIMO-IBFD system that can transmit and receive multiple data stream at the same time in the single band, and analyze the system. We have confirmed that MIMO-IBFD system requires multiple RF cancellation and multiple Digital cancellation techniques. In simulation, we have analyzed characteristic of received signal on MIMO-IBFD system, and evaluate system performance of conventional
MIMO system and MIMO-IBFD system. As simulation results, we have confirmed that MIMO-IBFD system can transmit and receive multiple data stream at the same time in the single band by using multiple RF and digital cancellation techniques. Additionally, we have confirmed that BER performance of
MIMO-IBFD system with low-level QAM modulation is similar to performance of
MIMO system, and BER performance of
MIMO-IBFD system with high-level QAM modulation is degraded in comparison with
MIMO system with high-level QAM modulation. We can confirm that MIMO-IBFD system requires high level self-interference cancellation technique in order to use high level modulation.
Design of Amplify-and-Forward Helper Stations for Cellular Networks with Device-to-Device Links
Chung, Jihoon ; Kim, Donggun ; Sung, Youngchul ;
The Journal of Korean Institute of Communications and Information Sciences, volume 41, issue 5, 2016, Pages 539~545
DOI : 10.7840/kics.2016.41.5.539
In this paper, the use of an amplify-and-forward (AF) helper station in a cellular network with device-to-device (D2D) communication links is considered to enhance D2D rates and control the interference caused by D2D users to the cellular network. Two design criteria for the AF helper station are considered to improve the overall system quality-of-service (QoS). One is maximization of the worst D2D user rate under a constraint on interference caused by D2D users to the cellular network and the other is its dual, i.e., minimization of interference caused by D2D users to the cellular network with minimum rate guarantee for each D2D user. It is shown that the considered problems reduce to semi-definite programming (SDP) problems. Numerical results show that the proposed AF helper station significantly improves the system performance.
Transmitting Devices Selection Based on Viewpoint Popularity for Wireless Free-Viewpoint Video Streaming
Koo, Jae-Woo ; Cho, Young-Jong ; Kang, Kyungran ;
The Journal of Korean Institute of Communications and Information Sciences, volume 41, issue 5, 2016, Pages 546~554
DOI : 10.7840/kics.2016.41.5.546
Free-viewpoint video (FVV) is a synthesization technology that generates a virtual viewpoint video using multiple videos recorded via wireless devices at heterogeneous locations. In order to introduce a new service that grafts the FVV onto the real-time streaming service using wireless devices, we need to overcome several constraints. Two main factors of those constraints are the limited wireless capacity that are shared fairly by multiple devices, and the transmission time constraint with which live streaming services have to comply. Therefore, for optimal quality of entire videos, a set of transmitting devices should be effectively selected depending on the condition of wireless channel and the required video popularity of specific viewpoint requested from users. For optimal selection, this study proposes a heuristic algorithm that takes into account the aforementioned factors from possible wireless transmission error behaviors and the requested viewpoint popularity. Through analysis and simulation, we show that with this algorithm, quality of most popular viewpoint videos is guaranteed. Furthermore, performance comparison against the existing scheme which is based only on the location of recording devices is made.
Centralized TDMA Slot Assignment Scheme Based on Traffic Direction for QoS Guarantee in Unmanned Robot Systems
Han, Jina ; Kim, Dabin ; Ko, Young-Bae ; Kwon, DaeHoon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 41, issue 5, 2016, Pages 555~564
DOI : 10.7840/kics.2016.41.5.555
This paper proposes a time slot allocation scheme for military patrol environments. This proposal comes from analysis of traffic properties in a military patrol environment. In the near future, robots are expected to explore enemy grounds and measure threat, taking the place of human patrol. In order to control such robots, control messages must be extremely accurate. One mistake from the control center could cause a tragedy. Thus, high reliability must be guaranteed. Another goal is to maintain a continual flow of multimedia data sent from patrol robots. That is, QoS (Quality of Service) must be guaranteed. In order to transmit data while fulfilling both attributes, the per-path based centralized TDMA slot allocation scheme is recommended. The control center allocates slots to robots allowing synchronization among robots. Slot allocation collisions can also be avoided. The proposed scheme was verified through the ns-3 simulator. The scheme showed a higher packet delivery ratio than the algorithm in comparison. It also performed with shorter delay time in the downlink traffic transmission scenario than the algorithm in comparison.
Priority-Based Dynamic Intent Assignment Method in Wi-Fi Direct Environments
Lee, Jae-ho ;
The Journal of Korean Institute of Communications and Information Sciences, volume 41, issue 5, 2016, Pages 565~573
DOI : 10.7840/kics.2016.41.5.565
Wi-Fi Direct standard technology(Wi-Fi Peer to Peer Technical Specifications v1.2, 2010) was designed for allowing peer to peer communication between two or more devices and various products which have been currently manufactured such as smart phone and smart TV have already provided this technical function. In this technology the role of Coordinator in Wi-Fi infrastructure would be matched to GO(Group Owner) which needs relatively high energy resource and computation power due to the high probability for allowing 3rd-party connection, however, the current standard specification would be limited in terms of energy distribution because it has not included a process to determine the role of GO. To address above problem, this paper classified considerable parameters into the general parameters for the physicality of devices and the specific parameters for considering the role position depending on use-case scenario, and proposed a new method called DIVA to help efficiently determining GO role from the member devices of Wi-Fi Direct network. Furthermore the effect of this mechanism was proved via simulation-based experiments.
Robust Obstacle Detection and Avoidance Algorithm for Infrastructure-Based Vehicle Communication Under Signal Interference
Choi, Byung Chan ; Kwon, Hyuk Chan ; Son, Jin Hee ; Nam, Haewoon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 41, issue 5, 2016, Pages 574~580
DOI : 10.7840/kics.2016.41.5.574
In this paper, we will introduce the system that can control multiple vehicles on the road through Single Board Computers and V2I (Vehicle-To-Infrastructure). Also, we will propose the group evasive maneuver decision algorithm, which plays a critical role in deciding whether the vehicles in the system have to conduct evasive maneuvers to avoid obstacles on the road. In order to test this system, we have utilized Wi-Fi and TCP/IP for establishing the communication between multiple vehicles and the relay server, and observed their driving states on the road with obstacles. During the experiments, we have discovered that our original decision algorithm possesses high failure rate when there is frequency interference in ISM (Industrial Scientific Medical) band. In order to reduce this failure rate, we have implemented the data transition detector. This paper will focus on how the use of data transition detector can affect the reliability of the system under the frequency interference of ISM band. If this technology is improved and applied in the field, we will effectively deal with such dangerous situations as multiple collision accidents through vehicle-to-vehicle communication or vehicle-to-infrastructure communication. Furthermore, this can be applied to the autonomous driving technologies. This can be used as the reference data for the development of the similar system.
Security Analysis and Improvements of Authentication Protocol for Privacy Protection in RFID Systems
Kim, Jiye ; Won, Dongho ;
The Journal of Korean Institute of Communications and Information Sciences, volume 41, issue 5, 2016, Pages 581~591
DOI : 10.7840/kics.2016.41.5.581
RFID(Radio Frequency IDentification) is a key technology in ubiquitous computing and is expected to be employed in more fields in the near future. Nevertheless, the RFID system is vulnerable to attacks by eavesdropping or altering of the messages transmitted in wireless channels. In 2013, Oh et al. proposed a mutual authentication protocol between a tag and a reader in RFID systems. Their protocol is designed to resist location tracking for privacy protection. However, all tags and readers use only one network-wide key in their protocol and tags are usually vulnerable to physical attacks. We found that their protocol is still vulnerable to tag/reader impersonation attacks and location tracking if an attacker obtains the network-wide key from a tag. In this paper, we propose a security improved authentication protocol for privacy protection in RFID systems. In addition, we demonstrate that the proposed scheme is efficient in terms of computation and communication costs.
LSTM Language Model Based Korean Sentence Generation
Kim, Yang-hoon ; Hwang, Yong-keun ; Kang, Tae-gwan ; Jung, Kyo-min ;
The Journal of Korean Institute of Communications and Information Sciences, volume 41, issue 5, 2016, Pages 592~601
DOI : 10.7840/kics.2016.41.5.592
The recurrent neural network (RNN) is a deep learning model which is suitable to sequential or length-variable data. The Long Short-Term Memory (LSTM) mitigates the vanishing gradient problem of RNNs so that LSTM can maintain the long-term dependency among the constituents of the given input sequence. In this paper, we propose a LSTM based language model which can predict following words of a given incomplete sentence to generate a complete sentence. To evaluate our method, we trained our model using multiple Korean corpora then generated the incomplete part of Korean sentences. The result shows that our language model was able to generate the fluent Korean sentences. We also show that the word based model generated better sentences compared to the other settings.
Identification of Advantages and Disadvantages Relative to Competitors of Politicians According to the Narrative Styles by Applying Voice Analysis
Choi, Ji Hyun ; Cho, Dong Uk ; Lee, Bum Joo ; Kim, Chan Jung ; Jeong, Yeon Man ;
The Journal of Korean Institute of Communications and Information Sciences, volume 41, issue 5, 2016, Pages 602~609
DOI : 10.7840/kics.2016.41.5.602
In a smart society, politicians analyze the big data of voters to build a favorable political positions. In other words, a variety of digital footprints uploaded in SNS or Internet are used to set the election strategies and political directions. In comparison, it is difficult for voters to extract intention information about how politicians are performing a political acts. Therefore, it is important that voters need to analyze what intention of politicians are like for two way interaction between voters and politicians. For this, in this paper, we want to do the identification by analyzing IT technologies to narrative styles of politicians who pursue relative advantages or gains compared to other competitors. The experiments will be carried out to identify about what relative advantages compared to other competitors by narrative styles of next presidential candidates who are expected to run into the next presidential election by analyzing the usual audio interviews.