• Journal of Fashion Business
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• v.20 no.2
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• pp.134-148
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• 2016

In this study, we determined the characteristics and importance of market maven to today's fashion retailers. Market maven is defined as an individual who is highly involved in the marketplace and takes a role as an information diffuser. In order to identify market maven, a total of 415 data were collected from 30-40 consumers who purchased fashion items from the various types of retailers. The data were divided into three groups based on the average score of summated market maven's scale, and the high group was referred to as "market mavens." Results suggested that the market mavens existed in the fashion retailing market and presented the differences from the other two groups. The market maven group spent more and purchased more fashion items than the other groups. With respect to shopping behavior, the market maven group was more likely to browse and bargain hunt when shopping, and showed higher mean scores on impulse buying and overall satisfaction. In addition, market maven tended to purchase fashion items from different types of retailers including online channel. Accordingly, market mavens seemed to present common characteristics with heavy browser, recreational shopper, and/or multi-channel shopper. Market mavens showed shopping enjoyment characteristics when searching for market-related information from various retailers, hence this segment should be the essential target market in the multi-channel retailing environment.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.3
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• pp.439-448
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• 2017

It is news from nowhere that post-quantum cryptography has side-channel analysis vulnerability. Side-channel analysis attack method and countermeasures for code-based McEliece cryptosystem and lattice-based NTRU cryptosystem have been investigated. Unfortunately, the investigation of the ring-LWE cryptosystem in terms of side-channel analysis is as yet insufficient. In this paper, we propose a chosen ciphertext simple power analysis attack that can be applied when ring-LWE cryptography operates on 8-bit devices. Our proposed attack can recover the key only with [$log_2q$] traces. q is a parameter related to the security level. It is used 7681 and 12289 to match the common 128 and 256-bit security levels, respectively. We identify the vulnerability through experiment that can reveal the secret key in modular add while the ring-LWE decryption performed on real 8-bit devices. We also discuss the attack that uses a similarity measurement method for two vectors to reduce attack time.

• Korean Journal of Optics and Photonics
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• v.33 no.6
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• pp.245-251
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• 2022

We have developed a multi-channel fiber laser for tiled laser beam combining and a laser output array system for multi-beam alignment. The fiber laser is a master oscillator power amplifier configuration that has a common seed, a preamplifier, and a 7-channel amplifier. The output power of each channel is more than 10 W. The laser output array system is a packed cylindrical configuration for a high fill-factor, and it has capabilities for collimation and tilt control with built-in PZT. Multi-beam alignment to a target is successfully implemented using PZT controlled with a stochastic parallel gradient descent (SPGD) algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.11
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• pp.1566-1573
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• 2021

Rendezvous is a process that assists nodes in a Cognitive Radio Networks (CRNs) to discover each other. In CRNs where a common control channel is unknown and a number of channels are given, it is important how two nodes find each other in a known search region. In this paper, I have proposed and analyzed a channel hopping sequence using Sidel'nikov sequence by which each node visits an available number of channels. I analyze the expected time to-rendezvous (TTR) mathematically. I also verify the Rendezvous performance of proposed sequence in the view of TTR under 2 user environment compared with JS algorithm and GOS algorithm. The Rendezvous performance of proposed sequence is much better than GOS algorithm and similar with JS algorithm. But when M is much smaller than p, the performance of proposed sequence is better than JS algorithm.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.6 s.348
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• pp.1-8
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• 2006

In the asynchrous OFCDM(Orthogonal Frequency and Code Division Multiplexing) system, a three-step cell search algorithm is performed for the initial synchronization in the following three steps: OFCDM symbol timing, i.e., Fast Fourier Transform(FFT) window timing is estimated employing guard interval (GI) correlation in the first step, then the frame timing and CSSC (Cell Specific Scrambling Code) group is detected by taking the correlation of the CPICH(Common Pilot Channel) based on the property yeilded by shifting the CSSC phase in the frequency domain. Finally, the CSSC phase within the group is identified in the third step. This paper proposes a modification code(PCSSCG:Patial Cell Specific Scrambling Code Group) of the conventional CPICH based cell search algorithm in the second step which offers MS(Mobile Station) complexity reductions with the nearly same performance. The proposed method is to be compared and verified through the computer simulation.

• Journal of Broadcast Engineering
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• v.11 no.1 s.30
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• pp.107-115
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• 2006

In the environment of single application data broadcasting, only one application can be serviced at a specific time on one channel. To overcome this, we developed the structure and the method of operation for multi-applications which are fully conformant to the ACAP (Advanced Common Application Platform), and modified data broadcasting system to support multi-applications. In multi-application environment, broadcasters can service multiple applications simultaneously at a specific airtime on one channel so users can enjoy services selectively according to their preferences. In this paper, we present an example of multi-application service which was developed to make an experiment before servicing them to users on the air. The core of the multi-application is a manager application which manages other ordinary applications, so we describe the function and structure of the manager application, and then present the experimental results to show that the proposed method is the proper model for multi-applications.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.5
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• pp.907-915
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• 2003

A very efficient packet transmission scheme is needed in the radio environment where radio resource is insufficient as compared with the environment of the wired communication. In general, dual mode packet transmission scheme is used broadly. Packets are transmitted through the dedicated or common chamois according to a switching criterion. The general criteria are the length and generation frequency of packet, that is, large and frequent packets are transmitted using a dedicated channel and small and infrequent packets are transmitted using a common channel. The performance of dual mode packet transmission scheme is closely related to the switching criteria. However, it is very difficult to find the optimal switching point because that is not fixed but variable according to the environment such as traffic load, length of generated packets, and the number of channels. In this paper, a new scheme for the dual mode packet transmission scheme using a dynamic switching threshold is proposed where the switching threshold is not fixed but variable according to the network environment. The performance of the proposed method is analyzed using a simulation. From the simulation results, it is shown that the performance of the proposed scheme is not very influenced by the network environment unlike the conventional dual mode packet transmission scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.8B
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• pp.910-920
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• 2011

In a heterogeneous wireless environment, a variety of Radio Access Technologies (RATs) coexist. Since the number of RATs is anticipated to increase in the near future, it is desirable to have radio and network resources managed in a cooperative manner using the Common Radio Resource Management (CRRM) strategy. In order to make RAT-specific radio resources manageable in CRRM, this paper proposes the Analytical Network Process (ANP) based resource management scheme that efficiently allocates resources among heterogeneous wireless networks. The proposed ANP-based method is flexible enough to be used in any network environment and can consider a multitude of decision factors. In addition, the proposed scheme uses a radio bandwidth model, which properly reflects transmission rates under given channel conditions, as the actual radio resources to be allocated. The model considers the AMC (Adaptive Modulation and Coding) scheme that is widely used in current broadband wireless access technologies, and thus, packet service characteristics, such as response time, can be analyzed. The effectiveness and flexibility of the proposed method are demonstrated by implementing a number of existing factors on heterogeneous networks environment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.1
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• pp.139-149
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• 2007

Asynchronous OFCDM(Orthogonal Frequency and Code Division Multiplexing) systems must have a cell search process necessarily unlike synch개nous systems. this process is hewn initial synchronization and a three-step cell search algorithm is performed for the initial synchronization in the following three steps: OFCDM symbol timing, i.e., Fast Fourier Transform(FFT) window timing is estimated employing guard interval (GI) correlation in the first step, then the frame timing and CSSC(Cell Specific Scrambling Code) group is detected by taking the correlation of the CPICH(Common Pilot Channel) based on the property yielded by shifting the CSSC phase in the frequency domain. Finally, the CSSC phase within the group is identified in the third step. This paper proposes a modification group code with two or three block of the conventional CPICH based cell search algorithm in the second step which offers MS(Mobile Station) complexity reductions. however, the effect of the reduction complexity leads to degradation of the performance therefore, look for combination to have the most minimum degradation. the proposed block type group code with suitable combinations is the nearly sane performance as conventional group code and has a complexity reduction that is to be compared and verified through the computer simulation.

• The Journal of the Acoustical Society of Korea
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• v.25 no.3
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• pp.113-120
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• 2006

This paper is concerned with a equalization technique for Orthogonal Frequency Division Multiplexing (OFDM) systems based on a block type pilot arrangement over slow fading channels. The bit rates obtained in underwater channels are relatively modest compared to some other communication channels such as cellular phones or indoor wireless systems. Consequently. the Doppler effect is the important parameter in tracking a channel. In case of a coherent demodulation scheme, the residual mean phase errors due to Doppler frequency may be fatal for the performance of the system. The equalizer could not solely handle mean Doppler shift. To account for the common Doppler effect a phase error tracking loop is used with the frequency equalizer. so that the rotation errors are avoided. Furthermore. simulations show that we can reduce the computational load of the tracking loop with negligible effect on performance.