• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.18 no.6
• /
• pp.565-575
• /
• 2009

A forklift (also called a lift truck) is a powered industrial truck that is used to lift and transport materials. It has become an indispensable piece of equipment in manufacturing and warehousing operations. The modem forklift is equipped with automatic transmission to meet the requirement of loading and easy operation of the vehicle. This paper proposes the design of TECU(Transmission Electronic Control Unit) which is applied to PSD322-Axle transmission. Garofalo's control technique is generally used to the automatic transmission. We consider the work quality and market requirement that does not want to control engine throttle. This paper proposes new controller system which guarantees efficient speed changes with simple system. This new system does not control the engine throttle spontaneously. But it has the load of engine and vehicle as a maximum disturbance. The scope of the disturbance is limited to the stoll area of the torque converter. This paper proposes a ideal control commander that converges relative velocity of the input and ouput of a clutch into a zero. We design linear controller to execute the idea control commander. We applied the control algorithm to the forklift of PSD322-Axle type and the performance of this controller was verified.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.19 no.9
• /
• pp.669-678
• /
• 2007

In this study, the ventilation characteristics is investigated numerically of the longitudinal ventilation method in the curved long road tunnel. Numerical work has been conducted for the jet fan location by utilizing the commercial finite-volume code, FLUENT. Configuration of the tunnel is three-lane, 1600 m long, $120m^2$ in area, 3000 m curvature radius. The velocity profile, distribution of mono-dioxide carbon and flow rate of air are examined in the tunnel. Through the analysis, it is found that the difference of ventilation flow rate Is a little by the jet fan location, but tunnel outlet setup (CASEIII) of jet fans is the most efficient concerned with CO concentration.

• International Journal of Automotive Technology
• /
• v.7 no.1
• /
• pp.17-23
• /
• 2006

An experimental study was carried out to obtain the fundamental data about the effect of sub-chamber on pre-mixture combustion. A eve (constant volume combustor) divided into a sub-chamber and a main chamber was used in this experiment. The volume of the sub-chamber was varid trom $0.45\%$ to $1.4\%$ about the whole combustion chamber. The sub-chamber has twelve narrow radial passage holes and a spark plug to ignite the pre-mixture. As the ignition occurs in the sub-chamber by a spark discharge, burned and unburned gas including a great number of radicals is injected into the main chamber, then the multi-point ignition occurs in the main chamber. The combustion pressure is measured to calculate the burning velocity mainly as a function of the sub-chamber volume, the diameter of the passage holes, and the equivalence ratio. In the case of RI (radical ignition) methods, the overall burning time became very short and the maximum burning pressure was slightly increased as compared with that of SI (spark ignition) method. The optimum design value of the sub-chamber is near 0.11 $cm^{-l}$ in the ratio of total area of holes to the sub-chamber volume.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.12 no.3
• /
• pp.83-97
• /
• 2009

The objects of study is to propose criteria for physical river disturbance assessment and as case study to show the application results for river improvement. For this purpose, the river disturbance assessment method for past disturbance process and the present-day potential natural state of stream is proposed. To assess the disturbance of the Youngcheon River caused by river improvement, One ares of Nam River was selected for the reference reach and two areas of Youngcheon River were selected for the comparison reach. And these reaches were surveyed and analyzed according to applying criteria of the river disturbances assessment. The assessment indices were physical factors as like epifaunal (bottom), embededness, velocity/depth regime, sediment deposition, channel flow status, channel alteration, frequency of riffles, bank stability, vegetative protection and riparian zone etc. The results showed that physical river environment in Youngcheon River area was disturbed by artificial revetment and bed excavation, consequently this disturbance give rise to impact of ecosystem in river. Hereafter, the criteria for river disturbance assessment are needed to consider various river characters as bed materials and bed slop etc.

• Korean Institute of Interior Design Journal
• /
• v.17 no.4
• /
• pp.84-91
• /
• 2008

The objective of this study is to investigate how visitors' behavior change in relation to the pattern of exhibition in art museum. For the purpose Busan Museum of Modern Art was selected as the sample in this study. And two patterns of exhibition, namely the planar exhibition and the three dimensional exhibition, were surveyed using the tracking movement method. The data gathered from random-sampling 60 visitors in a art museum was analyzed by the correlation analysis and T-test. The results are as follows; 1) There is no meaningful difference in visitors' behavior by the exhibition pattern in terms of their viewing area, viewing time, viewing distance, viewing velocity, viewing rate. 2) In contrast, there is meaningful difference in terms of the number of stops by visitors and the time spent without movement to see the objects; visitors stopped more often and stayed longer within the three dimensional exhibition space than the planar exhibition in a art museum. In sum, visitors extrinsically show no big behavioral difference between the planar exhibition and the three dimensional exhibition, but much difference in the way they communicate with objects; they show more active behavior within the three dimensional exhibition space.

• Korean Journal of Applied Biomechanics
• /
• v.26 no.4
• /
• pp.391-396
• /
• 2016

Objective: This study aimed to evaluate and identify variables for the standing balance of elderly subjects with different balancing abilities by using Kinect and Wii Balance Board. Method: The Berg Balance Scale (BBS) test was performed in 40 elderly subjects aged ${\geq}65years$ who can perform daily activities. The participants were divided into two groups, the healthy seniors (n = 20, BBS score ${\geq}52$) and the seniors with balancing problems (n = 20, BBS score < 52). Each group performed two standing tests (eyes open and eyes close) with two devices (Kinect and Wii Balance Board). The root mean square (RMS), mean distance (MDIST), range of distance (ROD), mean velocity, and 95% ellipse area were calculated from the measured data. Results: Among the calculated variables, RMS, MDIST, and ROD in the mediolateral direction showed significant differences between the two groups and a negative correlation with BBS scores. Conclusion: The results of the present study show that simple standing balance of the elderly can be measured with Kinect and Wii Balance Board, which are low-cost, easy to carry, and easy to use, by using the selected variables.

• Journal of Mechanical Science and Technology
• /
• v.19 no.12
• /
• pp.2312-2320
• /
• 2005

The aerodynamic effects of leading-edge accretion can raise important safety concerns since the formulation of ice causes severe degradation in aerodynamic performance as compared with the clean airfoil. The objective of this study is to develop a numerical simulation strategy for predicting the particle trajectory around an MS-0317 airfoil in the test section of the NASA Glenn Icing Research Tunnel and to investigate the impingement characteristics of droplets on the airfoil surface. In particular, predictions of the mean velocity and turbulence diffusion using turbulent flow solver and Continuous Random Walk method were desired throughout this flow domain in order to investigate droplet dispersion. The collection efficiency distributions over the airfoil surface in simulations with different numbers of droplets, various integration time-steps and particle sizes were compared with experimental data. The large droplet impingement data indicated the trends in impingement characteristics with respect to particle size ; the maximum collection efficiency located at the upper surface near the leading edge, and the maximum value and total collection efficiency were increased as the particle size was increased. The extent of the area impinged on by particles also increased with the increment of the particle size, which is similar as compared with experimental data.

• Geosciences Journal
• /
• v.22 no.6
• /
• pp.1027-1039
• /
• 2018

Seismic attributes are often used to identify lithology and evaluate reservoir properties. However, interpretation based only on structural attributes and without knowledge of the Vp/Vs ratio can limit the ability to evaluate changes in heavy oil reservoirs. These limitations are often due to less obvious impedance differences. In order to investigate pieces of evidence of a heavy-oil shaly-sand reservoir from seismic data, besides geochemistry, we studied seismic attributes and characterized the reservoir using seismic stack data and well logging data. The study area was the Muglad rift basin in South Sudan. We conducted a seismic complex analysis to evaluate the target reservoir. To delineate the frequency responses of the different lithological units, we applied the spectral decomposition method to the target reservoir. The most unexpected result was continuous bands of strong seismic reflectors in the target reservoir, which extended across the borehole. Spectral decomposition analysis showed that the low-frequency zone of 25 Hz dominant frequency was consistent with instantaneous attributes. This approach can identify lithology, reveal frequency anomalies, and filter the stacked section into low- and high-frequency bands. The heavy-oil reservoir zones exhibited velocity attenuation and the amplitude was strongly frequency dependent.

• Journal of International Academy of Physical Therapy Research
• /
• v.11 no.4
• /
• pp.2244-2252
• /
• 2020

Background: Thera-Band, Narrow squats, Kinesiology taping helps in the reduction of loading on the knee joints. Despite the fact that the varus knee negatively affects the alignment of the lower extremities, most of the studies have analyzed each independently. Objectives: To investigate the effects of a complex exercise program consisting of elastic band exercises and squat exercises on the distance between the inner knees and balance in young adults with genu varum. Design: A cluster randomized controlled trial. Methods: The complex exercise group performed resistance exercises using an elastic band. The taping group used kinesiology tape on the vastus lateralis and biceps femoris. To select those to be included in the study, we measured the distance between the knees using digital Vernier calipers and to measure the balance ability, we used a balance training system. The data were analyzed with the independent t-test and paired t-test. Results: The study indicated a significant difference in the distance between the knees between the two groups, but no significant differences in the dynamic balance between the groups. Also, the static balance comparison between the groups according to the intervention method included the trace length, C90 area, C90 angle and velocity. There were no significant differences in the static balance between the groups. In addition, the complex exercise program was more effective than taping. Conclusion: The results of this study demonstrate that the complex exercise program and taping decrease the between both the knee and increase the balance.

• Journal of ILASS-Korea
• /
• v.27 no.1
• /
• pp.1-10
• /
• 2022

In this study, an experimental investigation on the effects of the pressure ratio on the wall-impingement spray characteristics of nitrogen gas using a compressed natural gas (CNG) injector was conducted. The transient development of the impingement spray was recorded by a high speed camera with Z-type Schlieren visualization method. The spray behavior under various pressure ratio conditions were analyzed. The experimental results showed that the pressure ratio has positive effect on the development of spray wall-impingement. The effects of the above factor were evaluated in a constant volume chamber at atmospheric conditions. The data from test showed that, with the increase of the pressure ratio, the spray tip penetration (STP) quickly increases before the impingement and gradually increases after the impingement. Additionally, the spray velocity first increases and then sharply decreases on regardless of the injection pressure level. As the spray spreading angle increases, spray area and volume increases rapidly with the increase in STP at the beginning of injection, and finally entered a stable range, has a great correlation with the increase of pressure ratios.