• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2000년도 봄 학술발표회논문집
• /
• pp.389-396
• /
• 2000

A three-dimensional finite element dynamic analysis was conducted to evaluate the effects of reducing cross beams from a simply supported straight P.S.C girder bridge. Two analyses were performed on the P.S.C girder bridge; one with 7 cross beams which is commonly used as current standard, and the other with 3 cross beams. A frequency analysis was conducted first in order to establish the dynamic characteristics of the bridge and determine an appropriate time step to use in the time history analyses. To assess the function and effectiveness of the cross beams, time history analysis was conducted for aforementioned two analysis cases. In the analysis, the complete model was subjected to a loading condition corresponding to the one passing truck loading. Several results of deflection, bending moment and shear forces were compared for two cases. From the analysis results, reduction of cross beams was found to have only a minimum effect on the response of the bridge. The maximum deck slab bending moment was found to decrease. This decrease should result in smaller flexural crack widths in the deck slab, which may lead to an improved deck performance.

• 대한조선학회논문집
• /
• 제61권1호
• /
• pp.1-7
• /
• 2024

Underwater sound speed is an important analysis parameter on an estimation of the underwater radiated noise (URN) emitted from vessels. This paper aims to present an underwater sound speed measurement procedure using a cross-correlation of time-domain acoustic signals and validate the procedure through an experiment in a reverberant water tank. For the purpose, time-domain acoustic signals transmitted by a Gaussian pulse excitation from an acoustic projector have been measured at 20 hydrophone positions in the reverberant water tank. Then, the sound speed in water has been calculated by a linear regression using 190 cross-correlation cases of distances and time lags between the received signals and the result has been compared with those estimated by the existing empirical formulae. From the result, it is regarded that the presented experimental procedure to measure an underwater sound speed is reliably applicable if the time resolution is sufficiently high in the measurement.

• 대한산업공학회지
• /
• 제37권4호
• /
• pp.342-349
• /
• 2011

This paper considers the inbound and outbound truck scheduling problem in a cross docking terminal. The unloading process from inbound trucks and loading process to outbound trucks are assumed to be performed within a time window. If some items are not able to be loaded to their scheduled outbound trucks within the time window, they are stored in the terminal and shipped using the truck visiting the next time window. The objective of this paper is to schedule inbound and outbound trucks to minimize the number of items unable to ship within the time window. A mathematical model for an optimal solution is derived, and a rule-based local search heuristic algorithm and genetic algorithm (GA) are proposed. The performance of the algorithms are evaluated using randomly generated several examples.

• 아동학회지
• /
• 제7권1호
• /
• pp.67-84
• /
• 1986

The purpose of the present research was to investigate cross-modal transfer, especially tactual-to-visual transfer in infancy and to study the relation between failure of cross-modal transfer performance and length of familiarization period. The subjects of this study were 60 infants, 10 boys and 10 girls at each level: six, nine, and twelve months of age. All were normal, healthy, full-term babies. The mothers' educational achievement was controlled at more than 12 years of schooling. There were two separate experimental conditions, one 30-sec and one 60-sec familiarization period. Each experimental condition consisted of a tactual familiarization and a visual recognition memory test. Each child was presented with these 2 sets of cross-modal stimuli in one of the 2 experimental conditions. Infants' visual responses in the visual recognition memory test were videotaped for 20 seconds. Visual fixation time to novel and familiar stimuli was observed throughout the test. The data was analyzed with t-test, percentage of total fixation time to novel stimuli, and ANOVA. The results showed that: 1) Significant differences were found in the cross-modal transfer performance from touch to vision between the 3 age groups. This is, 6 and 9 month old infants didn't show cross-modal transfer in the 30-sec condition, but 12 month old infants did show cross-modal transfer in the 30-second. 2) In all 3 age groups, no significant differences were found in cross-modal transfer performance between the two conditions.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2010년도 춘계 학술발표회
• /
• pp.862-870
• /
• 2010

This thesis has been researched on optimized design method for the total cross section of embankment considering the fact that the size of embankment cross section is directly related with economic efficiency when dam designing. In general, embankment cross section of fill dam is either determined by cohesion and angle of internal friction, a strength parameter of embankment materials or by permeability of embankment. Therefore the size of embankment cross section depending on strength parameter of embankment materials was determined by using MIDAS-GTS program through stress-seepage coupled analysis at the time of fill dam design. As a result, determination of embankment cross section was more affected by the size of central core and permeability rather than by slope stability by shear strength and it was revealed that in case of embankment height being over 20m, stability against infiltration and slope action could be secured only when embankment slope is at least over 1:2.5. In addition, it was also revealed that in case of making the size of central core exceeding specification standard, total cross section of embankment could be reduced considerably and at the time of embankment design, adequate size and appropriateness of embankment cross section could be determined with referring the table suggested by this study.

• 소음진동
• /
• 제7권5호
• /
• pp.747-756
• /
• 1997

Wigner-Ville distribution which is a time-frequency analysis has a fatal drawback, when the signal has multiple components. This is the cross-talk and often causes a neagative value in the distribution. Wingner-Ville distriution is an expression of power, therefore the cross-talk must be avoided. Smoothing the Wigner-Ville distribution by convoluting it with a window, is most commonly used to reduce the cross-talk. There can be infinite number of distributions depending on the windows. But, the smoothing reduces resolution in time-frequency plane; this motives to design a more effective window in reducing cross-talk while remaining resolution. The domain in which the cross-talk and legitimate components can be easily distinguished, is the ambiguity function. In the ambiguity function domain, the legitimate components appear as linear lines passing through the orgine. But, the cross-talk is widely distributes in the ambiguity function plane. Based on the relative distributions of cross-talk and legitimate components, rotating window can be designed to minimize cross-talk. Applying the rotating window to the ambiguity function corresponds to smoothing the Wigner-Ville distribution. Therefore, the effects of rotating window is estimated in terms of the bias error due to smooting the Wigner-Ville distribution. By applying the rotating window, not only the Wigner-Ville distribution but also its properties are changed. The properties of the new distribution are checked, in order to complete analyzing the rotating window.

• 한국의류학회지
• /
• 제37권4호
• /
• pp.467-481
• /
• 2013

The study examined the main effect of the reward channel and reward time of customer loyalty programs for on-offline shopping channels; in addition, it investigated the interaction effect of the reward channels and merchandise as well as the interaction effect of the reward time and merchandise. An online apparel shopping web experiment was conducted with a 2 (reward channel: online channel reward vs. offline channel reward) ${\times}2$ (reward time: immediate vs. delayed) ${\times}2$ (merchandise: online channel product vs. offline channel products) between-subject factorial design. An online shopping channel was considered the core-shopping channel and a department store was considered the cross-shopping channel. Loyalty program value, core-channel loyalty and cross-channel loyalty were measured as dependent variables. A total of 845 shoppers (who had experiences in shopping in both channels) participated in the experiment. The results of the study revealed (1) the main effect of the reward channel on loyalty program value, core-channel loyalty and cross-channel loyalty [online>offline channel rewards], (2) the main effect of reward time on loyalty program value, core-channel loyalty and cross-channel loyalty [immediate>delayed reward], and (3) the interaction effect of the reward channel and merchandise on loyalty program value, core-channel loyalty, and cross-channel loyalty. (4) Finally the study found that loyalty program value affected cross-channel loyalty indirectly through core-channel loyalty. This study suggested diverse theoretical and managerial implications for multi-channel retailers.

• 한국통신학회논문지
• /
• 제34권4B호
• /
• pp.419-427
• /
• 2009

본 논문에서는 OTA(One Time Authentication)키를 이용한 사용자 인증, 디바이스 인증 그리고 상호 인증 모듈을 사용하여 공인인증서 비용과 도용문제를 해결하고, 홈 네트워크 사업지석 서비스에 가입할 필요가 없는 이중 인증 기법인 DA-UDC(Double Authentication User Device Cross) 모듈을 설계하였다. 홈 서버는 사용자 아이디, 디바이스 아이디 그리고 세션키를 확인하는 1단계 인증 과정을 통과한 사용자에 대해 OTA키 생성에 필요한 홈서버 공개키를 전송하고, 사용자가 생성한 OTA키를 확인하는 2단계 인증과정을 수행한다. 이때 생성되는 DA-UDC 모듈의 OTA키는 생성될 때마다 변경되도록 설계하였다. 따라서 DA-UDC 모듈은 이중 인증 과정을 수행함으로써 사용자 아이디 및 디바이스 아이디 노출을 대비하였고 OTA키 사용으로 악의의 사용자로부터 홈 네트워크의 인증 보안을 강화시켰다. 또한, BA-UDC 모듈은 단 1회의 인증 연산 횟수를 가지므로 기존의 인증 시스템보다 처리 속도가 빠르며, 별도의 인증키를 사용하므로 데이터 전송량은 많지만 보안측면에 강화시켰다고 볼 수 있다.

• 비교문화연구
• /
• 제30권
• /
• pp.245-258
• /
• 2013

This paper analyzes the current Chinese prepositions that represent space and time, which ultimately indicate the concept of Direction. having this in mind, the concept of time that the prepositional phrases 'qian+Tn' and 'Tn+qian' possess can be understood by analyzing the prepositions that 'qian' to make time expressions. also, this paper establishes a systemic framework that will help not only students but also professors to use the preposition 'qian' in order to make correct time expressions.

• 한국운동역학회지
• /
• 제21권3호
• /
• pp.259-268
• /
• 2011

This study aimed to examine the kinematic characteristics of the national elite cross-country skiers' double poling technique and to provide the quantitative data for better performance. Four male elite cross-country roller skiers skied maximum velocity with Double Pole technique. The cycle characteristics with angles of elbow, hip, and knee joint were analyzed. The results showed that CM velocity of the body was increased with the third cycle, the cycle time and length were also increased. The poling time and recovery time rate showed with 32.79%, 67.44% respectively. The joint angles with elbow, hip and knee were $106^{\circ}$, $133.14^{\circ}$ $156.87^{\circ}$ at pole in event, $158.94^{\circ}$, $65.7^{\circ}$, $140.19^{\circ}$ at pole out event. Elite skiers should decrease double poling time rate and increase recovery time rate in order to improve the double poling performance. The cycle length and velocity of the double poling should be increased for the better performance. The elbow angle should be minimized at pole in event with maximum extension until pole out event. The hip and knee angles should be increased for the recovery phase.