• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.4
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• pp.355-364
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• 2016

Recently, a 3,250 meter-long tunnel was constructed beneath the sea bed formed of composite sedimentary soils to transport reusable waste heat gas of industrial complex in the west coast of Korea. Some risks such as machine settlement always exist due to the uncertainties of geological and construction factors during the subsea shield TBM tunnelling. In this construction site, the deviation of tunnel alignment caused by shield TBM settlement was occurred during excavation. It was examined that the lack of bearing capacity of soft clay was a main cause. This paper evaluates the risk of shield TBM tunnelling considering the ground conditions. Correlation between machine settlement and its advance rate was evaluated through the analytical equation in which bearing capacity is considered and a 3-D numerical analysis which can simulate the TBM advance condition (in other words, the dynamic condition). It was found out that a shield TBM could settle due to the insufficient bearing capacity of soft clay layers. In order to prevent such the problem, the best advance rate proper to the ground characteristics is needed to be applied. In the ground conditions of the section of interest, it was turned out that if the shield TBM advance rate was maintained between 35 mm/min and 40 mm/min, the machine settlement could be avoided.

• Journal of the Korean Chemical Society
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• v.33 no.4
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• pp.371-378
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• 1989

Kinetics of the substitution reaction of [pt[dien]X]$^+$(X = $Cl^-$, $Br^-$, $I^-$) with NO2- in aqueous solution were investigated by a spectrophotometric method at $20-35^{\circ}C$ and 1-1500 bars. The rates of these reactions were increased with raising temperature and pressure. The relative reactivities of replaceable ligands in [pt[dien]X]$^+$ follow the order ($Cl^-$ > $Br^-$ > $I^-$). Activation volumes (${\mid}{\Delta}V^{\neq}{\mid}$) were large negative values and decreased with raising temperature. First ($k_1$) and second($k_2$) order rate constants of these reactions were determined at $25^{\circ}C$ and both $k_1$ and $k_2$ were increased with raising pressure and activation volumes (${\Delta}{V_1}^{\neq}$, ${\Delta}{V_2}^{\neq}$) for the $k_1$ and $k_2$ path were large negative values respectively. The $k_1$ and $k_2$ of these reactions were determined at 1 bar and these values were increased with raising temperature. Activation parameters of $k_1$ and $k_2$ path were determined, therefore it can be inferred frp, these results that the substitution reactions of [pt[dien]X]$^+$ with ${NO_2}^-$ proceed through on associative (A) mechanism independent of a leaving groups and reaction paths.

• Journal of the Korean Chemical Society
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• v.38 no.12
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• pp.915-920
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• 1994

The Menschutkin type reactions of substituted (Z)-benzyl (X)-arenesulfonates with substituted(Y)-pyridines were studied by the electroconductometric method in acetonitrile at $35\circC$. Hammett $\rho$ values were calculated by the second order rate constants for the reaction of substituted (Z)-benzyl (X)-arenesulfonates with substituted (Y)-pyridines. The negative $\rho_Y$ values meant positive charge development on the nitrogen of pyridine at transition state owing to the charge development on the oxygen atom of benzenesulfonate. And the negative $\rho_Z$ values meant positive charge development on the benzylic carbon. Application of the multi-Hammett interaction,│$\rho_YZ$│ > │$\rho_XY$│ > │$\rho_ZX$│, the Menschutkin type reaction of substituted benzyl arenesulfonates with substituted pyridines was shown to be dissociative $S_N2$ mechanism.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.1
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• pp.126-136
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• 2014

In the Advanced Driver Assistance Systems (ADAS) of smart vehicle and Intelligent Transportation System (ITS) for to detect the boundary of lane is being studied a lot of Hough Transform. This method detects correctly recognition the lane. But recognition rate can fall due to detecting straight lines outside of the lane. In order to solve this problems, this paper proposed an algorithm to recognize the lane boundaries and the accumulator cells in Hough space. Based on proposed algorithm, we develop application for Android was developed by H/W verification. Users of smart phone devices could use lane detection and lane departure warning systems for driver's safety whenever and wherever. Software verification using the OpenCV showed efficiency recognition correct rate of 93.8% and hardware real-time verification for an application development in the Android phone showed recognition correct rate of 70%.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.4
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• pp.3-9
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• 2017

Due to difficulties of continuous electric power provision to underwater communication nodes, the efficient power usage is highly required in underwater network protocol. In this paper, we studied the energy efficient MAC(Medium Access Control) protocol for underwater network supporting mobile nodes such as UUV(Unmanned Underwater Vehicle) and AUV(Autonomous Underwater Vehicle). The mobile nodes could waste the electric power in vain when the receiver moves out of the radio propagation coverage during the data exchange and thus the transmitted data fails in reaching the receiver. Expecially, such a failure is much more obvious in underwater acoustic channels since the propagation delay is about $10^5$ times slower than in terrestrial radio channels. This proposed mobility-MAC controls the data dropping stochastically in the Dropping Zone by considering the receiver's location and moving velocity. In conclusion, this selective dropping method not only improves latency and throughput by reducing invalid droppings but also boosts power efficiency by valid droppings.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.69-77
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• 1991

A collision-free trajectory planning algorithm using an iterative learning concept is proposed for dual robot arms in a 3-D common workspace to accurately follow their specified paths with constant velocities. Specifically, a collision-free trajectory minimizing the trajectory error is obtained first by employing the linear programming technique. Then the total operating time is iteratively adjusted based on the maximum trajectory error of the previous iteration so that the collision-free trajectory has no deviation from the specified path and also that the operating time is near-minimal. To show the validity of the proposed algorithm, a numerical example is presented based on two planar robots.

• 한국경영정보학회:학술대회논문집
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• 2008.06a
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• pp.909-920
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• 2008

기술이 급속도로 발전하고 과거 자연 독점을 이루고 있던 많은 서비스 산업의 규제가 완화되면서 경쟁이 더욱 치열해지고 있다 기존 기업들은 신규 시장 진입 기업들을 방해하기 위하여 진입장벽을 높이기도 하고 기존의 인프라를 이용하여 더욱 뛰어난 기술력을 선보이기 위하여 노력한다 하지만 대부분의 서비스 기업들의 경우 이동통신 산업처럼 새로운 서비스가 시장에 진입하게 되면 많은 사람들의 관심이 늘어나고 이로 인해 기존 서비스가 시장에서 퇴출되는 둥의 어려움도 가지고 있다. 또한 독과점 형태를 이루고 있던 기업들은 시장 진입 기업에 대해 방심하고 있다. 갑작스러운 경쟁 체제에 미숙한 대응 방안으로 인하여 더욱 어려움을 겪기도 한다 반면에, 소비자의 경우 신규 서비스 초반 많은 관심을 가지고 이용 서비스를 신규 서비스로 옮기기도 하지만 서비스 품절, 이용용이성, 유용성에 의하여 지속적으로 이용하기도 하고 다시 기존 서비스를 이용하기도 한다. 따라서 경쟁 체제에서의 시장 환경에서 고객 만족도를 높여 결과적으로 고객 충성도를 높이는 전략은 기존 기업뿐만 아니라, 신규 진출 기업에게도 매우 중요한 과제가 되고 있다. 최근 유료방송시장의 기술이 발전하고 IPTV라는 새로운 서비스가 출시됨에 따라 기존의 Cable TV 는 시장 점유율이 잠식당하고 있다 IPTV 의 유료방송 시장으로의 진출로 인해 Cable TV 의 많은 가입자들이 IPTV 로 이용서비스를 옮기는 것을 방지하기 위하여 고객 만족을 높여 결과적으로 고객 의 충성도를 높여 기존 고객의 이탈을 방지하기 위한 전략이 필요하다. 유료방송서비스 외에도 많은 서비스 산업 내에서 경쟁이 치열해지면서 기존 기업들이 고객의 이 탈을 방지하기 위하여 고객 만족도를 높이는 방안에 대한 연구가 필요하다 본 연구에서는 유료방송 시장을 분석하여 서비스 산업에서 고객만족을 높이기 위한 방안에 대하여 연구해보고자 한다. 기존 연구의 서비스 품절, 이용용이성, 유용성에 대한 연구를 기초로 하여 고객 성향, 신규 서비스의 효용성이라는 변수를 추가하여 분석한 결과 고객 성향 및 신규 서비스의 효용성이라는 변수도 역시 고객 만족도와 고객 충성도에 많은 영향을 주는 것으로 나타났다.

• Science of Emotion and Sensibility
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• v.16 no.2
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• pp.235-248
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• 2013

In this study, the effects of driver's neuroticism on situation awareness(SA), eye movement(EM), and driving performance were examined. In Experiment 1, in which static driving scenes were presented, it was found that the drivers of higher neuroticism showed shorter percentage of dwell time and less percentage of fixation counts for the peripheral area than those of lower neuroticism, although SA scores yielded no difference between the two neuroticism groups. In Experiment 2, differences in the drivers' driving performances as well as SA and EM as a function of neuroticism were compared using driving simulation. The results of Experiment 2 showed the followings. First, contrasting to Experiment 1, the high neuroticism group showed lower SA score than low neuroticism group. Second, the pattern of EM was similar to those of Experiment 1. Third, high neuroticism group deviated more from center of road, and drove slower than low neuroticism group.

• Journal of the Korean Wood Science and Technology
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• v.43 no.3
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• pp.287-294
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• 2015

Relationship between growth rate and wood quality was investigated by mechanical properties with Alnus glutinosa L. (24 years old) from 4 different origins of seeds (Bulgary, Italy, United Kingdom and Yugoslavia). Compression strength was in the range of $231{\sim}326kgf/cm^2$, and there was some differences among different origins of seed. Wood cultivated from the seeds of Italy, United Kingdom, and Bulgary showed higher growth rate and had lower compression strength and compression young's modulus. Wood from Yugoslavia seed had the fastest growth rate with higher strength than other three origins of seed. Bending strength was in the range of $426{\sim}727kgf/cm^2$, and there was some differences among the origin of seed. Higher growth rate wood showed higher bending strength and young's modulus than other woods. Trees cultivated from Yugoslavia seed had two times in diameter than other different origins of seeds, also have compressive strength, bending strength than other origins, which can be recommended as best cultivar in Alnus glutinosa L.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.2
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• pp.148-161
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• 2015

The examples that used camera in the vehicle is increasing with the growth of the automotive market, and the importance of the image processing technique is expanding. In particular, the Lane Departure Warning System (LDWS) and related technologies are under development in various fields. In this paper, in order to improve the lane recognition rate more than the conventional method, we extract a Normalized Luminance Descriptor value and a Normalized Contrast Descriptor value, and adjust image gamma values to modulate Normalized Image Quality by using the correlation between the extracted two values. Then, we apply the Hough transform using the optimized accumulator cells to the four-channel ROI. The proposed algorithm was verified in 27 frame/sec and $640{\times}480$ resolution. As a result, Lane recognition rate was higher than the average 97% in day, night, and late-night road environments. The proposed method also shows successful lane recognition in sections with curves or many lane boundary.