• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.9
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• pp.880-886
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• 2014

Many railway signalling functions have increasingly depended on computer software with recent development in computing technology, leading to evolution into more flexible and intelligent railway signalling system. Meanwhile, software programs are likely to have many errors and the cost incurred by such errors has increased. Especially, if fatal software error occurs during railway operation, it may result in loss of lives. So the software verification and validation have become more important. It is needed for software functional safety tool to support these, but most commercial tools depend on direct access to the system's memory, resulting in many difficulties in application. Owing to such difficulties and complexity, they are rarely used in railway signalling system software validation. In this study, a new testing tool for software functional testing through an external interface that can be easily used in functional testing of software was developed. Such testing tool allows development and analysis of test cases for black-box testing through analysis of actually used interface protocols, leading to increased user convenience.

• The Journal of Fisheries Business Administration
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• v.41 no.3
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• pp.103-127
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• 2010

The FAO reports that IUU fishing activities have widespread economic, social, and management consequences, including depriving legitimate fishers of harvest opportunities. It affects all fisheries from small scale to industrial. It also affects the ability of governments to support sustainable livelihoods for fishers and, more broadly, to achieve food security. The complexity of IUU requires various measures to combat IUU fishing such as adoption of IUU vessel lists; stronger port State controls; improved monitoring, control and surveillance (MCS); implementation of market-related measures to help ensure compliance; and capacity-building assistance. Trade and market measures reduce opportunities for IUU fishing activities by precluding or impeding access to markets for IUU product in a manner consistent with international law. ICCAT, CCAMLR, and IATTC, have put in place trade tracking programs or catch documentation schemes, and WCPFC is considering such a program. Vessel lists assist enforcement authorities in determining which vessels are or are not authorized to be fishing or conducting fishing support activities in specified areas. A number of RFMOs maintain records of IUU vessels: CCAMLR, IATTC, ICCAT, NAFO, NASCO, NPAFC, WCPFC. Section 608 of the US MSRA calling on the Secretary of Commerce, in consultation with the Secretary of State, and in cooperation with relevant regional fishery management councils and any relevant advisory committees, to take actions to improve the effectiveness of international fishery management organizations in conserving and managing stocks under their jurisdiction. EU IUU Regulation entered into force on 1 January 2010, was intended to regulate the highly complex multi-channel fisheries supply system of the European Community (EC) in an effort to improve global fisheries sustainability.

• Fashion & Textile Research Journal
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• v.15 no.5
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• pp.743-752
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• 2013

Consumers can share their diverse opinions about products due to the increased popularity of smartphones and the internet that enables increased access to the websites and encourages the use of 'SNS' (Social Network Services). Social commerce has expanded rapidly as a mainstream online shopping channel over the past year, compelling consumers to spend more money vis-$\grave{a}$-vis social commerce websites. This allows individuals to see different lists of prices for specific products; however, it is also likely to lead to serious compulsive buying. Despite these changing trends, earlier studies have been limited to factors that affect impulse purchases vis-$\grave{a}$-vis Internet shopping malls; therefore, in is salient to conduct research on consumer spending habits related to social commerce websites. This study describes the characteristics of consumers and utilizes social commerce websites as parameters for the impact of impulsive shopping based on a survey of 300 women in their 20's who have experienced impulse buying vis-$\grave{a}$-vis social commerce websites. This study shows that: First, discounts, product scarcity and social commerce site's reputation affect impulse buying when consumers buy products from the social commerce websites. Second, variables on the characteristics of the personal experiences, interests, and self-control also stimulate impulsive purchases.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.1
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• pp.8-22
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• 2014

In the past few decades, CMOS logic technologies and devices have been successfully developed with the steady miniaturization of the feature size. At the sub-30-nm CMOS technology nodes, one of the main hurdles for continuously and successfully scaling down CMOS devices is the parametric failure caused by random variations such as line edge roughness (LER), random dopant fluctuation (RDF), and work-function variation (WFV). The characteristics of each random variation source and its effect on advanced device structures such as multigate and ultra-thin-body devices (vs. conventional planar bulk MOSFET) are discussed in detail. Further, suggested are suppression methods for the LER-, RDF-, and WFV-induced threshold voltage (VTH) variations in advanced CMOS logic technologies including the double-patterning and double-etching (2P2E) technique and in advanced device structures including the fully depleted silicon-on-insulator (FD-SOI) MOSFET and FinFET/tri-gate MOSFET at the sub-30-nm nodes. The segmented-channel MOSFET (SegFET) and junctionless transistor (JLT) that can suppress the random variations and the SegFET-/JLT-based static random access memory (SRAM) cell that enhance the read and write margins at a time, though generally with a trade-off between the read and the write margins, are introduced.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.5
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• pp.32-39
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• 2009

Compressed Sensing is a method to sample analog signals at a rate under the Nyquist rate. With this scheme, it is possible to represent signals with a relatively smaller number of measurements than that of the conventional sampling method, and the original signals are reconstructed with high probability from the acquired measurements using the linear programming. Compressed sensing allows measurement time and/or the amount of ADC (analog-to-digital converter) resources for the signal acquisitions to be reduced. In this paper, we presents the backgrounds of the compressed sensing, a way to acquire measurements from an analog signal with a random basis, and the signal recovery method. Also we introduce applications of compressed sensing in wireless communications.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.5
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• pp.16-24
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• 2007

Wireless mesh network extends the limited coverage of conventional wireless service from one-hop access point to wider area. It is recognized as an important issue to provide seamless handoff in the wide coverage of wireless mesh network. A long handoff delay may cause high packet loss and disconnection of service, degrading the network performance. The handoff delay is mainly introduced from the channel scanning process obtaining information to make handoff decision and the unnecessary handoffs due to inaccurate handoff decision. In this paper, we propose the handoff algorithm based on one-way trip time (OTT) to expedite the handoff procedure. As compared to the handoff algorithm based on the receiving signal power, the proposed algorithm takes advantage of OTT to obtain the necessary handoff information in a relatively shorter time and reduce the unnecessary handoffs. The performance of proposed algorithm is evaluated through the simulations. It is verified that the proposed handoff algorithm can effectively enhance the handoff accuracy, and therefore reduce the handoff delay and unnecessary handoffs.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.8
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• pp.75-81
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• 2008

The authors present a more accurate analysis of the bit error rate (BER) performance for multicode code division multiple access (CDMA) systems equipped with a multipath interference canceler (MPIC) over multipath fading channels. At first, we consider the problem of previous researches. It is that the previous analyses do not match with simulations even in the case without MPIC. This mismatch also causes the difference between the analysis and simulations when an MPIC is applied. Therefore, what is needed is to verify the reason of this mismatch at the initial stage. Numerical results obtained from the proposed analytical method indicate that the performance mismatch between the previous analysis and simulations is caused by not fie Gaussian approximation which is generally used at the performance analysis of CDMA systems but the additional Gaussian approximation (AGA) for multipath interferences. Based on this effect, we propose a more accurate performance analysis not using AGA and its accuracy is verified by simulations. Furthermore, it is confirmed that the proposed analysis presents an analytical lower bound which can be achieved by MPIC.

• Journal of IKEEE
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• v.16 no.2
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• pp.138-144
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• 2012

In this paper, a semi-analytical approach is proposed for DSF(Decode and Selective Forward)-Relay MC-CDMA(MultiCarrier-Code Division Multiple Access) systems over multipath Rayleigh fading channels. Considering BER(bit error rate) performance and complexity, the MMSE-C(Minimum Mean squared Error-per subCarrier) is used as the combining method for MC-CDMA systems. At first, the analytical method based on error-events at relay nodes for DSF-Relay schemes is utilized in order to derive the averaged BER. Then, the averaged BER is expressed as the form considering possible all error-events. Also, proposed semi-analytical expressions have been verified by comparing with simulation results. Finally, it is verified that the derived analytical expressions can be a frame work to cover different multipath Rayleigh fading channel conditions and to measure the upper performance for DSF-Relay MC-CDMA systems.

• The Journal of the Convergence on Culture Technology
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• v.4 no.1
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• pp.285-290
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• 2018

Vehicular ad hoc network (VANET) is one of the future communication technologies in which it offers safe-driving information and Internet access for both drivers and passengers by communicating among cars on the road. In case of applying Content Centric Network (CCN) rather than TCP/IP over VANET, called VCCN, it can provide efficient multicast communication of shared information among participating cars as well as offer corresponding one-to-one communications. This paper introduces SUMO for simulating traffic flows, VANET for car-to-car ad hoc communications, and CCN for a future Internet architecture. In addition, it compares and analyses the transmission performance of moving cars over VCCN. According to the simulation results using SUMO and VCCN, the larger the packet size, the better the transmission performance. In addition, VCCN provides higher packet transmission rate than that of TCP/IP when the clients shares the same contents. Furthermore, the overall data reception rate exceeds the physical transmission channel rate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.6
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• pp.681-688
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• 2016

Several VHF bands for the use in analog communications has been changed to those for the use in new maritime digital communications by WRC-12. ITU-R M. 1842-1 has been also standardized, recommending the characteristics of maritime digital communication systems. In addition, a Shipborne Ad-hoc Network (SANET) has been introduced by IMO in order to provide ships, which cannot be connected to a shore directly, with maritime digital data exchange services with the help of ad-hoc communication. In this paper, several functionalities of the SANET, including channel access, route determination to a shore, and data exchange, are verified via sea trials. It is expected that the SANET can be applicable to collecting and analyzing maritime information, facilitating the entry and departure of vessels, and the communication infrastructure of e-navigation.