• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.3
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• pp.595-603
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• 2017

We propose a scheme to reduce the time for the SSL/TLS handshake by embedding it into the TCP 3-way handshake. The scheme can be selectively applied on the standard TCP for making the SSL/TCP handshake happen within the TCP handshake, rather than performing the TCP handshake and SSL/TLS handshake in sequence. We implemented a prototype of the scheme and did some experiments on its performance. Experimental results showed that, compared to the sequential handshakes of the TCP and the SSL/TLS, the time reduction achieved by the scheme varied in the range of 3.2% and 14%(when the elapsed time by the ping program from the client to the server was 11.6ms). The longer the time measured by the ping program, which would grow as the propagation and queuing delays do, the larger the reduction rate. It accords with the supposition that the reduced time due to the scheme will increase in proportion to the amount of the elapsed time measured by the ping program.

• Journal of Korea Multimedia Society
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• v.16 no.4
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• pp.430-443
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• 2013

The recognition of current position and road surrounding of car is very important to driver for safe driving. This paper presents the recognition technique of the road traveling environment using position information hiding and viewpoint transform that monitors the information of road furniture and signature and notifies them to driver. The proposed scheme generates the road images into which the position information are hided, from car camera and GPS module and provides the road information to driver through the viewpoint transformation and the road signature detection. The driving tests with camera and GPS module verified that the position information hiding takes about 66.5ms per frame, the detection rate of road signature is about 95.83%, and the road signature detection takes about 227.45ms per frame. Therefore, we know that the proposed scheme can recognize the road traveling environment on the road video with 15 frame rate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.5
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• pp.486-496
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• 2013

Time synchronization in underwater environment is challenging due to high propagation delay and mobility of sensor nodes. Previous researches do not consider practical issues affecting on the accuracy of time synchronization such as high-channel access delay and relative position between sensor nodes. Also, those protocols using bidirectional message exchange shorten the network lifetime and decrease the network throughput because numerous transmission, reception and unnecessary overhearing can be occurred. Therefore, in our research, we suggest enhanced time synchronization based on features of underwater environment. It controls the instant of transmission by exploiting the feature of an oceanic movement and node deployment. Moreover, the protocol uses more accurate time information by removing channel access delay from the timestamp. The proposed scheme is also practical on the underwater sensor network requiring low-power consumption because the scheme conducts time-synchronization with smaller transmission and reception compared with previous works. Finally, simulation results show that the proposed protocol deceases time error by 2.5ms and 0.56ms compared with TSHL and MU-Sync respectively, reducing energy consumption by 68.4%.

• Journal of Broadcast Engineering
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• v.21 no.5
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• pp.662-671
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• 2016

In this paper, we propose a wireless video transmission system, providing medium and long communication distance in the 5.8GHz band to decrease the loss of video data. Beamforming with multiple antennas in a radio environment to enable more than 10km communication distance and an image transmission method that combines the retransmission to MCS(modulation and coding scheme) are applied. By applying the proposed method in the indoor environment of 80dB attenuation using the payload size of 1000 bytes, the packet loss rate of at least 0.92% is achieved through the FPING with the time-out of 10ms. The transmission distance of 21.2Km is achieved with the transmission rate of 13Mbps in the outdoor environment.

• Food Science of Animal Resources
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• v.31 no.4
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• pp.603-608
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• 2011

The objective of this study was to investigate factors related to carcass traits of Hanwoo. In the statistical model developed in this study, slaughterhouse, carcass year, carcass month and sex effects were used as fixed effects and carcass traits (carcass weight, marbling score, loineye muscle area, backfat thickness and meat yield index) as covariations. The grading service data for 285,515 Hanwoo, which were evaluated by Animal Products Grading Service from 2005 to 2007, were used in this study. The partial R-square values of the fixed effects and the marbling score (MS), loineye muscle area, back-fat thickness, meat yield index and carcass weight (CW) on auction prices (AP) of the carcass and carcass price (CP) of the animals were estimated. The most important estimated trait in AP was MS. However, CW is the most important estimated trait on the CP and the MS also has secondly significant effect on the CP. In conclusion, MS as well as CW should maximize the farmer profits and establish a breeding scheme for Hanwoo.

• JSTS:Journal of Semiconductor Technology and Science
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• v.9 no.3
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• pp.160-165
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• 2009

A 12b 2 MS/s cyclic ADC processing 3.3 Vpp single-ended rail-to-rail input signals is presented. The proposed ADC demonstrates an offset voltage less than 1 mV without well-known calibration and trimming techniques although power supplies are directly employed as voltage references. The SHA-free input sampling scheme and the two-stage switched op-amp discussed in this work reduce power dissipation, while the comparators based on capacitor-divided voltage references show a matched full-scale performance between two flash sub ADCs. The prototype ADC in a $0.18{\mu}m$ 1P6M CMOS demonstrates the effective number of bits of 11.48 for a 100 kHz full-scale input at 2 MS/s. The ADC with an active die area of $0.12\;mm^2$ consumes 3.6 m W at 2 MS/s and 3.3 V (analog)/1.8 V (digital).

• Korean Journal of Culture and Social Issue
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• v.14 no.1
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• pp.101-123
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• 2008

We investigated the implicit representations of success/failure associated with mother in male and female college students. In study 1, participants were presented 'mother' or 'basket' as a context prime and 'success' or 'failure' related words as second primes for 100ms, and were asked to make lexical decisions about 'accept' or 'reject' related words and non-words after 150 ms (SOA 250ms). Results revealed that lexical decision times on the mother condition were more rapid than the ones on the basket condition, and lexical decision times on the acceptance condition were more rapid than the ones on the rejection condition, and female participants showed shorter times than male students did. In study 2, we divided participants into four groups by gender and attachment style, Results showed that the interaction between success/failure and acceptance/rejection was statistically significant, that is, quickest lexical decision times on the success-acceptance condition, and slowed times on failure-acceptance, failure-rejection, and success-rejection condition in order. On the other hand, no significant differences between high and low attachment group were found in males, but significant three-way interactions were found in females. In highly attached females, lexical decision times in success-acceptance condition were not differed from ones in success-rejection condition, and slowed times in failure-rejection condition. Low attached females showed very rapid times in success-acceptance condition, but very slow times in success-rejection condition. The results were discussed in terms of self-positivity and success/failure scheme depending on gender and attachment styles.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.7A
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• pp.710-716
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• 2007

In this paper, a new scheme of downlink co-channel interference (CCI) cancellation in OFDM cellular networks is introduced for users at the cell-edge. Coordinated symbol transmission between base stations (BS) is operated where the same symbol is transmitted from different BS on different sub-carriers. At the mobile station (MS) receiver, we introduce a soft decision maximum likelihood CCI canceler and a modified maximum ratio combining (M-MRC) to obtain an estimate of the transmitted symbols. Weights used in the combining method are derived from the channels coefficients between the cooperated BSs and the MS. Simulations show that the proposed scheme works well under frequency-selective channels and frequency non-selective channels. A gain of 9 dB and 6 dB in SIR is obtained under multipath fading and flat-fading channels, respectively.

• Smart Structures and Systems
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• v.4 no.5
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• pp.629-640
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• 2008

A new algorithm is proposed to determine optimal accelerometer locations (OAL) when a structure is identified by frequency domain system identification (SI) method. As a result, a guideline is presented for selecting OAL which can reflect modal response of a structure properly. The guideline is to provide a minimum number of necessary accelerometers with the variation in the number of measurable target modes. To determine OAL for SI applications effectively, the modal sensitivity effective independence distribution vector (MS-EIDV) is developed with the likelihood function of measurements. By maximizing the likelihood of the occurrence of the measurements relative to the predictions, Fisher Information Matrix (FIM) is derived as a function of mode shape sensitivity. This paper also proposes a statistical approach in determining the structural parameters with a presumed parameter error which reflects the epistemic paradox between the determination of OAL and the application of a SI scheme. Numerical simulations have been carried out to examine the proposed OAL algorithm. A two-span multi-girder bridge and a two-span truss bridge were used for the simulation studies. To overcome a rank deficiency frequently occurred in inverting a FIM, the singular value decomposition scheme has been applied.

• ETRI Journal
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• v.31 no.6
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• pp.717-724
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• 2009

This paper describes a 1.2 V 12 b 60 MS/s CMOS analog front-end (AFE) employing low-power and flexible design techniques for image signal processing. An op-amp preset technique and programmable capacitor array scheme are used in a variable gain amplifier to reduce the power consumption with a small area of the AFE. A pipelined analog-to-digital converter with variable resolution and a clock detector provide operation flexibility with regard to resolution and speed. The AFE is fabricated in a 0.13 ${\mu}m$ CMOS process and shows a gain error of 0.68 LSB with 0.0352 dB gain steps and a differential/integral nonlinearity of 0.64/1.58 LSB. The signal-to-noise ratio of the AFE is 59.7 dB at a 60 MHz sampling frequency. The AFE occupies 1.73 $mm^2$ and dissipates 64 mW from a 1.2 V supply. Also, the performance of the proposed AFE is demonstrated by an implementation of an image signal processing platform for digital camcorders.