• International Journal of Advanced Culture Technology
• /
• v.3 no.1
• /
• pp.161-168
• /
• 2015

This article aims to apply a friction stir spot welding for producing a lap joint of AA1100 aluminum alloy and SGACD zinc coated steel. The experiment was designed by MINITAB and then investigated the relation among the friction spot joint parameters. The experimental results are as follows. The friction spot joining could successively produce the lap joint of AA1100 aluminum alloy and SGACD zinc coated steel. Interaction between the rotate speed, the hold time and the tool insert speed affected to vary the tensile shear strength of the lap joint. The prediction of the optimized welding parameters that indicated the tensile shear strength of 1966 N was the rotated speed of 4000 rpm, the pin hold time of 6 sec, the pin insert rate of 6 mm/min with the S/N ratio of 66.56 that was higher than that of the total mean S/N ratio. The practical experiment of the predicted welding parameters indicated the tensile shear strength of 2165 N and had the S/N ratio of 66.70 that was higher than the predicted tensile shear strength.

• Journal of Korean Society of Transportation
• /
• v.27 no.3
• /
• pp.29-38
• /
• 2009

In Korea, large.scale housing complexes and residential areas began to appear in urban regions through urban plan projects from the 1970s. In addition, with the increase in the percentage of apartments in developed areas, road traffic noise at roadside apartments was raised as a new problem. Furthermore, since the late 1980s, apartments, which had been no taller than 15 stories, have grown higher to 20-30 stories and recently 40.story or higher apartments are being constructed, and as a result, residences are growing denser and road traffic noise is increasing in urban areas. Thus, the present study made a noise map using variables 'traffic volume' and 'mean spot speed' among factors influencing roadside apartments, and examined the noise reduction efficiency of the variables. According to the results, traffic volume and speed limit were found to have an effect on a limited space, and the median bus lane system was found to have a slight effect on the roadside.

• Journal of Advanced Marine Engineering and Technology
• /
• v.31 no.1
• /
• pp.26-33
• /
• 2007

The intake swirl motion, as one of dominant effects for an engine combustion. is very effective for turbulence enhancement during the compression process in the cylinder of 2-valve engine. Because the combustion flame speed is determined by the turbulence that is mainly generated from the mean flow of the charge air motion in intake port system. This paper describes the experimental results of swirl flow and combustion characteristics by using the oil spot method and back-scattering Laser Doppler velocimeter (LDV) in 2-valve single cylinder transparent LPG engine using the liquid phase LPG injection. For this. various intake port configurations were developed by using the flow box system and swirl ratios for different intake port configurations were determined by impulse swirl meter in a steady flow rig test. And the effects of intake swirl ratio on combustion characteristics in an LPG engine were analyzed with some analysis parameters that is swirl ratio. mean flow coefficient, swirl mean velocity fuel conversion efficiency. combustion duration and cyclic variations of indicated mean effective pressure(IMEP). As these research results, we found that the intake port configuration with swirl ratio of 2.0 that has a reasonable lean combustion stability is very suitable to an $11{\ell}$ heavy-duty LPG engine with liquid phase fuel injection system. It also has a better mean flow coefficient of 0.34 to develope a stable flame kernel and to produce high performance. This research expects to clarify major factor that effects on the design of intake port efficiently with the optimized swirl ratio for the heavy duty LPG engine.

• Journal of Korean Society of Transportation
• /
• v.31 no.4
• /
• pp.47-57
• /
• 2013

This study aims at analyzing transportation equity between geographical areas of Gyonggi Province, by taking both the transportation infrastructure and travel behavior into account. Indicators of transportation infrastructure include the indices of road infrastructure, transit infrastructure and regional characteristics. Travel behavior concerns information from bus card data on a survey day. The hot-spot analysis conducted included spatial cluster analysis and global/local regression analyses. The analysis results identified geographical areas of four different classes of transportation equity, from the area with high level infrastructure surrounded by the areas with high level infrastructure (HH) to the area with low level surrounded by the areas with low level (LL). The area of HH type showed big numbers of passengers, trips and transfers, whereas the area of LL type shows big figures of internal trip frequency, travel time, travel distance, travel speed and transit fare. Global regression analysis showed that number of passengers, number of transfers, number of internal trips and mean travel speed are important to the level of transportation infrastructure. GWR with these four significant variables significantly improved the AICs and ANOVA results, which implies that the infrastructure is likely explained by travel characteristics differently between geographical areas in Gyonggi Province.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.9 no.6
• /
• pp.43-53
• /
• 2010

The increasing interest in the use of automated photographic equipment in Korea enables to detect speed violation and enforce traffic laws. Since 1996, Korean National Police Agency has been promoting a project for installation of Automated Speed Enforcement (ASE) system aiming at reduction of accidents. Recently, point to point speed cameras operate to measure a driver's average speed across length of road and/or the spot speed at individual camera sites along the road length. In this study, we were analyzed to driver's operating characteristics in point to point speed cameras. The point to point speed camera system has link-long influence on drivers and their speeds despite enforcement being visible only at the start and end of enforced road length. Then, mean and 85th percentile speeds were below speed limit along enforced road length by the two camers. Also, Female drivers were driving at low speed than male drivers along the road length.

• Journal of Korean Society of Transportation
• /
• v.18 no.5
• /
• pp.57-67
• /
• 2000

Two fuzzy travel time estimators for interrupted traffic flow were developed based on field survey data and simulation data 7hat is collected from DETSIM, which is microscopic traffic simulation model that car-following theory is applied. One is FETTOS(Fuzzy Estimator of Travel Time using Occupancy and Spot speed) and the other is FETTOS(Fuzzy Estimator of Travel Speed using Volume and Occupancy). Fuzzy logic controller was applied to the estimators to deal with non-linear relationship between traffic variables and travel time. According to results of simulation and field survey. estimation of travel time can be modeled by using percent occupancy better than any other traffic variables. Detector location from storyline and signal timing Plan of intersection are affected to estimate travel time. With a few findings, the estimator was constructed and its performance was tested for observed travel time data and simulated data. FETTOS which needs signal timing plan and detector location estimates travel time with accurate better than FETSVO does. However. FETSVO has excellent transferability because the estimator needs set of input data only; volume and time mean speed.