• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.33B no.1
• /
• pp.49-56
• /
• 1996

In this paper, as a new grey scale method for simple matrix LCDs, the grey scale method using the new code scheme was proposed. The experiment and the characteristic estimation for the new grey scale method were performed by the simulation of the 16 and 32 grey patterns and the calculation of the driving voltages. As a result of the experiment and the characteristic estimation, the 16 grey mode using the 3 bits code scheme, (7, 5, 3) has the maximum driving voltage which is reduced by 19% and 9.6% each compared with the values in the conventional grey modes discussed in this paper. And the extent of improvement in the driving voltage characteristics is increased much as the number of grey levels increases. On the other hand, as a result of the grey image estimation through the grey pattern simulation, the 3 bits 16 grey mode degrades the characteristics of the grey image more or less compared with the conventional grey method but the extent of this characteristic degradation is much reduced with the increase in the number of grey levels such as 32 grey scale, etc. Consequently the grey scale method using the new code scheme proposed in this paper is confirmed as a method that it minimized the degradation of grey characteristics and improves the driving voltage characteristics effectively.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.40 no.9
• /
• pp.801-805
• /
• 2016

In this paper, engine clutch engagement shock is analyzed during the mode change of plug-in hybrid electric vehicles. Multi-driving mode includes the EV (electric vehicle) mode, HEV (hybrid electric vehicle) mode, and engine operating mode. Depending on the mode change, the engine clutch is either engaged or disengaged. The magnitude of shock during clutch engagement is very important because it impacts vehicle acceleration and clutch synchronization speed, which affects ride comfort substantially. The performance simulator of plug-in hybrid electric vehicles was developed using MATLAB/Simulink. The simulation results show that the mode change control algorithm is necessary for minimizing shock during clutch engagement.

• Journal of IKEEE
• /
• v.26 no.3
• /
• pp.483-487
• /
• 2022

In this paper, we design a self-powered Arduino system for solar energy harvesting and explain its operation. To perform the operation, the Arduino system senses the amount of solar energy that changes every moment and adjusts the ratio of the active mode and sleep mode operation time according to a given solar light intensity. If the intensity of sunlight is strong enough, the Arduino system can be continuously driven in active mode and receive sufficient power from sunlight. If not, the system can run in sleep mode to minimize power consumption. As a result, it can be seen that energy consumption can be minimized by reducing power consumption by up to 81.7% when using sleep mode compared to continuously driving active mode. Also, when the light intensity is at an intermediate level, the ratio between the active mode and the sleep mode is appropriately adjusted according to the light intensity to operate. The method of self-control of the operating time ratio of active mode and sleep mode, proposed in this paper, is thought to be helpful in energy-efficient operation of the self-powered systems for wearables and bio-health applications.

• Journal of Korean Society for Atmospheric Environment
• /
• v.29 no.5
• /
• pp.656-667
• /
• 2013

The non-exhaust coarse, fine, and ultrafine particles were characterized by on-road driving measurements using a mobile sampling system. The on-road driving measurements under constant speed driving revealed that mass concentrations of roadway particles (RWPs) were distributed mainly in a size range of 2~3 ${\mu}m$ and slightly increased with increasing vehicle speed. Under braking conditions, the mode diameters of the particles were generally similar with those obtained under constant speed conditions. However, the PM concentrations emitted during braking condition were significantly higher than those produced under normal driving conditions. Higher number concentrations of ultrafine particles smaller than 70 nm were observed during braking conditions, and the number concentration of particles sampled 90 mm above the pavement was 6 times higher than that obtained 40 mm above the pavement. Under cornering conditions, the number concentrations of RWPs sampled 40 mm above the pavement surface were higher than those sampled 90 mm above the pavement. This might be explained that a nucleation burst of a lot of vapor evaporated from the interaction between the tire and the road pavement under braking conditions continuously occurred by cooling during the transport to the sampling height 90 mm, while, for the case of cornering situations, the ultrafine particle formation was completed before the transport to the sampling height of 40 mm.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.9 no.5
• /
• pp.457-466
• /
• 2004

In this paper, a modified converter is presented and analyzed to use as a photovoltaic converter. And also a new parallel driving scheme is proposed to increase output power and to reduce the output voltage ripple. The ratio of the output to the input voltage of the modified converter is equal to that of the boost converter. The difference between both converters is the composition of output terminal. Owing to the discrepancy, a working voltage of the output capacitor of the modified converter becomes lower, thus the capacitance value of the capacitor can be smaller than that of the boost converter. The proposed parallel driving is based on the modified converter and a current-mode-control method. It gives a good solution for alleviating the current sharing unbalance problem of conventional parallel operations. It reduces the output voltage ripple by means of increasing the equivalent switching frequency without additional switching losses. The validity of the proposed parallel driving strategy is verified through computer-aided simulations and experimental results.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.21 no.5
• /
• pp.778-783
• /
• 2012

Due to the increase of oil price, the needs of the reduction of the fuel cost is rising. Therefore, necessity of hybrid vehicle that runs with engine and the electric motor is on the rise. In order to improve the performance of hybrid vehicle, many researches is carried out. Hybrid vehicles have been developed with the various layout such as serial type, parallel type, power split type, and multi-mode type. The multi-mode hybrid vehicles are designed to show the efficient driving characteristics at low speed and high speed. But the multi-mode system have the problem such as frequent clutch engagement. Frequent clutch engagement causes the shock of vehicles, and the shock inhibits the ride comfort. In this study, automation mechanism of clutch operation is proposed to mitigate the shock at engaging clutch. For this purpose, the dynamic characteristics of motor control is numerically analyzed by using Matlab/Simulink.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.12 no.4
• /
• pp.81-87
• /
• 2016

Recently, as the heterogeneous network (HetNet) has been deployed widely to support various kinds of Radio Access Networks(RANs) with a combination of Macro, Pico, and/or Femto cells, research and standardization efforts have been very active regarding the concept of Licensed Shared Access (LSA) for supporting spectrum sharing. In order for a mobile device to efficiently support the spectrum sharing, the mobile device shall be reconfigurable, meaning that its radio application code has to be adaptively changed in accordance with the hopping of desired spectral band. Especially, Working Group 2 (WG2) of Technical Committee (TC) Reconfigurable Radio System (RRS) of European Telecommunications Standards Institute (ETSI) has been a main driving force for developing standard architecture for Multi-mode Mobile Device (MD) that can be applied to the LSA system. In this paper, we introduce the Multi-mode MD architecture for supporting LSA-based spectrum sharing. An implementation of a test-bed of Multi-mode MD is presented in order to verify the feasibility of the standard MD architecture for the purpose of LSA-based spectrum sharing through various experimental tests.

• Land and Housing Review
• /
• v.11 no.2
• /
• pp.1-14
• /
• 2020

The aim of this study is to empirically identify the differentiating characteristics of determinant factors on sing-person households' commuting mode choice compared to multi-person households' one in order to establish the customized police directions to decrease private car use in commuting. While the study use the 2% sample survey data on the population and housing in 2015, it employ multinomial logit models on relative choice probability of such alternative commuting modes as bus, subway or rail, and walking, rather than driving. As potential determinant factors, the study employs demographic, socio-economic, and housing and residential one for both models of single-person and multi-person households. The study finds that the behavior of commuting mode choice has distinctive difference by gender, marriage status, physical activity constraint, job type, residential period in current housing of the single-person household's workers compared to the multi-person households' ones. Based on the findings, the study deduce ten commuting policy directions customized for the single-person household.

• Journal of the korean Society of Automotive Engineers
• /
• v.6 no.4
• /
• pp.36-45
• /
• 1984

The relationship between vehicle driving pattern and fuel consumption in urban area was studied in Seoul along three representative routes using a test car equipped with all the instruments required for recording modes of traffic and measuring fuel consumption. Correlation with idle speed, fuel consumption and CO concentration of car in use was also measured. The average vehicle speed in Seoul was 31.4 km/h and the time spent in different modes was 23.0% in idle mode, 22.5% in acceleration mode, 32.4% in cruising mode and 22.3% in deceleration mode, respectively. Hence, traffic flow was suggested to be relatively smooth. Fuel consumption per unit distance, .phi. was closely related with trip time spent per unit distance, t, and correlation coefficient obtained from the test car was 0.925, and the relationship between .phi. and t was also obtained from the linear regression with the following equation. .phi.=42.87+0.38 t. Idle speed of vehicle in use was mostly adjusted low and cars which were over the permissible standard of CO concentration (4.5%) were 50% or more. As the idle speed decreased, the fuel consumption was decreased, while the CO concentration was increased. Therefore, the decrease of fuel consumption can not be expected with only a decrease in idle speed.

• Journal of the Korean Society of Safety
• /
• v.24 no.4
• /
• pp.1-10
• /
• 2009

The characteristics of smoke emissions from diesel heavy duty vehicles which weigh over 5.5 tons was investigated by driving the vehicles with both the Lugdown 3 modes in the chassis dynamometer and tree accelerating mode under no load. The vehicles include commercial vehicles such as bus, microbus, trucks and specialized vehicles, etc. The total numbers of the vehicles tested were 200. The light extinction method was used to measure the smoke emissions from the vehicles tail pipe. The values of the smoke emissions in the tree accelerating mode showed $0{\sim}20%$ band nearly independent of both the mileage and year of production of the tested vehicles, while those in the Lugdown 3 modes showed $0{\sim}99%$ of wide band. The correlation coefficients between the values of the smoke emissions with both the Lugdown 3 modes and the free acceleration mode were 0.12, 0.08, 0.12, respectively. The inspection with Lugdown 3 modes is better one than that with tree acceleration from the point of exact inspection of the diesel vehicles' smoke emission.