• 반도체디스플레이기술학회지
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• 제23권2호
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• pp.28-32
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• 2024

The personal mobility Sharing service is currently active. Especially, electric scooters are widely utilized because they can move comfortably at a high speed over a short distance with a simple driving method. Its driving method is easy, but there is no protection device to protect the bare body. So, there is a greater accident than other means of transportation, and if two people are on board, there is higher accident probability. However, since there is no specific ways to prevent multi-person boarding yet, we propose a multi-person boarding detection model using tilt and pressure sensor. The proposed method measures the tilt degree and direction by using a tilt sensor installed in the center of the board plate and detects multi-people riding.

• 한국엔터테인먼트산업학회논문지
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• 제13권5호
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• pp.229-238
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• 2019

본 연구는 운전자의 자기통제력, 운전행동과 운전스트레스의 관련성을 알아보고자 하였다. 본 연구는 2015년 4월 29일부터 7월 24일까지 광주·전남에 거주하고 운전면허를 소지하며 운전경험이 있는 운전자 180명을 대상으로 자기통제력, 운전행동, 운전스트레스에 대한 설문을 통해 자료를 수집하여, 운전자의 자기통제력, 운전행동과 운전스트레스의 관련성을 알아보았다. 연구 결과, 첫째, 운전자의 자기통제력이 운전행동의 실수, 위반, 착오와 운전스트레스의 진행 장애, 운전환경, 사고단속, 교통법규, 시간압력에 통계적으로 유의한 차이를 보였고, 운전자의 자기통제력이 높은 집단에서 운전행동과 운전스트레스의 하부 구성요인들은 낮았다. 둘째, 운전자의 자기통제력, 운전행동의 실수, 위반, 착오와 운전스트레스의 진행 장애, 운전환경, 사고단속, 교통법규, 시간압력 간에 상관관계가 있었다. 연구 결과를 종합하여 보면 운전자의 자기통제력, 운전행동과 운전스트레스는 서로 관련 있음을 알 수 있었다. 본 연구는 자기통제력, 운전행동과 운전스트레스로 인해 발생할 수 있는 교통사고를 예방하기 위한 기초자료로 활용할 수 있을 것이라 생각된다. 또한, 향후에는 다양한 지역에서 연구가 이루어지길 기대한다.

• 한국자동차공학회논문집
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• 제6권2호
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• pp.191-202
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• 1998

An electronic-hydraulic controlled line pressure system was suggested based on the mechanical controlled CVT base model. As a high level control strategy, a 3-D optimal line pressure map was obtained considering the driver's desire, driving conditions. Also, PID type low level controller was designed. Using the high level control strategy and the dynamic models of the base model CVT with electronic controlled line pressure system, performance simulations were carried out. It is seen from the simulation results that fuel economy of the electronic controlled strategy keeps the line pressure low, which results in the improved efficiency of the hydraulic system.

• 한국정밀공학회지
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• 제13권8호
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• pp.120-127
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• 1996

Anti-lock Brake System has been developed to reduce tendency for wheel lock and improve vehicle control during sudden braking on slippery road surfaces. This is achieved by controlling the braking pressure, avoiding wheel lock, while retaining handling and brake performance. This paper is concerned about pressurecharacteristics of hydraulic modulator. Experimental sets which is consists of hydraulic modulator, duty controller, pressure regulator, pressure senset is consuructed. System modelling and computer simulation are performed for comparison with experimental results. Brake wheel pressure are measured under various driving pulse. The result of experiment show fairly agreement with the simulation. As a result, it is known that wheel pressure is affected by duty ratio, orifice diameter through computer simulation.

• 대한의용생체공학회:의공학회지
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• 제44권2호
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• pp.157-165
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• 2023

The purpose of this study was to evaluate the importance of developing slim seats with ergonomic design to improve seat comfort and expand the interior space. Two seats were used for the experiment: a sample seat designed based on hip shape and spinal alignment and a normal seat with a flat design without curves. Subjects sat in both the sample seat and a normal seat applied to the vehicle simulator and the experiment was conducted. The next part of the experiment was conducted in two different postures: a driving posture and a relaxed posture. The subjects filled out a comfort questionnaire immediately after sitting and after 30 minutes. The results showed that the comfort in the sample seat was found to be more comfortable than the normal seat. However, no significant difference was noted for the relaxation posture. Pressure distribution was also recorded immediately after sitting and after 30 minutes. In the case of pressure distribution, it was confirmed that the pressure in the sample seat was more evenly distributed in both the driving and relaxed postures than in the normal seat. The results showed that the ergonomically designed sample seat greatly improved seating comfort and pressure distribution compared to the normal seat, which is a general vehicle seat design.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1991년도 추계학술발표회논문집
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• pp.5-10
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• 1991

There are many articles about the HID lamps about it's characteristics and simulation methods for lamps design or ballast design. For the eletronic ballasts of HID lamps, There are some problems caused by acoustic resonance which destabilizes the arc of HID lamps. So, some studies suggest the methods to avoid it. For example, the methods to avoid it. For example, the methods suggested are high frequency driving over 100kHz, and mixed frequency driving which alternates high frequency and low frequency, and square wave driving etc. This study suggests the electronic ballast of HID lamps which solves the problems of acoustic resonance, and which can control the luminance by constant current boosted chopper of which frequency is 30kHz and by the sqarewave driving of which frequency is 55.5Hz. As follows, we have the good eletronic ballast for HID lamps which has the characteristics of a light weight, and a function of luminance control and a high quality luminosity and which saves electrical energy.

• Journal of Biosystems Engineering
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• 제24권6호
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• pp.513-522
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• 1999

This study was performed to get the optimal operating conditions of an water-air compact heat pump system using R-134a. The experiments was done for three elvels of the air mass flow rate and the compressor driving speed during air-heating process. The temperature of the air at the condenser inlet and outlet was 17~23$^{\circ}C$, 36~44$^{\circ}C$, respectively. The average temperature of the refrigerant at the evaporator and condenser was 1$0^{\circ}C$, 6$0^{\circ}C$, respectively. The temperature of the refrigerant was not depending on the air mass flow rate and the compressor driving speed. The pressure of the refrigerant at the condenser inlet and outlet was ranged of 10~18.5kg/$\textrm{cm}^2$ and that at the evaporator was ranged of 3.1~3.3kg/$\textrm{cm}^2$. The pressure drop at the condenser and evaporator was about 1.5, 1.2 kg/$\textrm{cm}^2$, respectively. The performance of coefficient for air heating was about 3.3~4.0.

• 한국생산제조학회지
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• 제23권6호
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• pp.596-601
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• 2014

In this study, driving efficiency and the safety of motorcycle drivers due to the mounting gradient of motorcycle protective glass are investigated through flow analysis. Mounting gradients of motorcycle protective glass in models 1, 2, and 3 are $60^{\circ}$, $70^{\circ}$, and $80^{\circ}$, respectively. Wind velocity of 100 km/h is applied to the protective glass installed at the front of each model. The flow resistance values of models 2 and 3 are 1.2 and 1.5 times, respectively, that of model 1. The driving efficiency of model 1 is the highest among the three models. Pressure to the driver's face in models 2 and 3 is 1.2 times higher than in model 1. Because the pressure to the driver's face in model 1, with mounting gradient of $60^{\circ}$, is the lowest among the three models, model 1 is the safest. This result can be applied to improve the safety of motorcycle drivers.

• Applied Science and Convergence Technology
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• 제25권3호
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• pp.51-55
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• 2016

The surface treatment of a titanium implant is investigated with a non-thermal atmospheric pressure plasma jet. The plasma jet is generated by the injection of He and $O_2$ gas mixture with a sinusoidal driving voltage of 3 kV or more and with a driving frequency of 20 kHz. The generated plasma plume has a length up to 35 mm from the jet outlet. The wettability of 4 different titanium surfaces with plasma treatments was measured by the contact angle analysis. The water contact angles were significantly reduced especially for $O_2/He$ mixture plasma, which was explained with the optical emission spectroscopy. Consequently, plasma treatment enhances wettability of the titanium surface significantly within the operation time of tens of seconds, which is practically helpful for tooth implantation.

• 로봇학회논문지
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• 제16권2호
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• pp.86-93
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• 2021

This paper proposes a controller to regulate the supply pressure of the hydraulic power unit (HPU) for driving a bipedal robot. We establish flow rate models for charging accumulator, actuating joints and leaking from actuators and spool valves. This determines the pump driving motor speed to satisfy the demanded flow rate for operating the bipedal robot without the energy loss caused by the bypass through a pressure regulating valve. We apply proposed controller to an onboard HPU mounted on top of bipedal robot platform with twelve degrees of freedom. We implement air-walking motion and squat motion which require variable flow rate to the bipedal robot. Through this experiment, the energy efficiency of proposed controller was verified by comparing the electric energy consumed when the controller was applied and when the pump operated at constant speed. We also shows the capability of the HPU's control performance to regulate supply pressure.