• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.627-630
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• 1991

This study is about vector controlled inverter for high quality elevator drive that is to improve the settling accuracy of elevator car and passenger's comfort in commercial buildings. In this study, an instantaneous space vector control type inverter was used to reduce the torque ripple ant to improve the velocity follow-up. This method calculates Instantaneous actual output torque and flux of induction motor by voltage and current, then compares them with a reference values by a speed regulator. The outputs of comparators select a switching mode, for an optimal voltage vector. Also, this study used IGBT (Insulated Gate Bipolar-Transistor), a high speed switching element, to reduce sound noise level, and DSP (Digital Signal Processor) was used to improve the reliability of the control circuit by fully digitalization.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.45 no.1
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• pp.46-55
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• 2009

To compare and evaluate the suitability and comfort levels of the environment on board a stern trawl training ship, KAYA(GT: 1737 tons, Pukyong National University), with the international standardization guide ISO 6954:2000(E), measurements of the hull vibration on accommodation areas and working areas of the training ship from July 8 to July 10, 2008 were completed upon KAYA's linear sea route. The vibrations along the z-axis were measured with the use of a 3-axis vibration level meter, which included a marine vibration card. Results show accelerations of the vibrations on the passenger's accommodation area to be 42.0-115.8(average: 78.0, standard deviation(SD): 21.0) mm/$s^2$, which is largely below the permissible upper limit, but 75 % of the observation points exceeded the permissible lower limit of 71.5 mm/$s^2$, indicating a comfortable environment. The accelerations of the vibration in a frequency of 10-24Hz lowering the visual performance were measured at 2.5-12.0(average: 7.6, SD: 3.1) mm/$s^2$. The crew s accommodation area experienced vibration accelerations of 42.9-82.3(average: 93.1, SD: 53.1) mm/$s^2$, which is generally below the permissible upper limit of 214.0 mm/$s^2$, and 62.5% of the observation points did not exceed the permissible lower limit of 107.0 mm/$s^2$, denoting a level of comfort. The acceleration of the vibration in a frequency of 10-24Hz were 4.7-28.3(average: 12.4, SD: 8.8) mm/$s^2$. On the crew s working area the accelerations were measured at 86.9-153.9(average 119.3, SD 18.0) mm/$s^2$. These values were generally below the permissible upper limit of 286.0 mm/$s^2$ and only 12.5% of the observation points did not exceed the permissible lower limit of 143.0 mm/$s^2$, the level at which a high level of comfort is maintained. The accelerations in frequency of 10-24Hz and 30Hz were 9.1-29.8 (average 13.8, SD= 4.5) mm/$s^2$ and 8.9-13.7 (average 11.8, SD 2.1) mm/$s^2$, respectively. In conclusion the boarding environment of the training ship was good in general although an improvement of the vibration condition partially needed on the crew s accommodation area near the engine room.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.3
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• pp.35-46
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• 1997

In order to satisfy customer's requirements of ride comfort and high performance, it is necessary for designers to fully understand vehicle aerodynamics and wind noise of newly produced cars because characteristics of flow and wind noise are heavily dependent on each other. In this study numerical and experimental study have been carried out to analyse the effect of flow characteristics at around of rear view mirror on wind noise and soiling on the front S/W. As a result, it's found that the spiral flow mear the front pillar is weakened and spreaded because rear view mirror obstructs the flow. It is also shown that there is abrupt change of gradient of separa- tion line, separation area, intensity of spiral flow and turbulent kinetic energy with varying shape of neck and housing of rear view mirror.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.3
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• pp.214-222
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• 2012

Driver's feeling is variously affected by lots of components such as engine, frame, wheels, and seats during the operation of automobiles. The main objective of this research is to identify the correlation between subjective evaluation and vibration metrics that was set by ISO to investigate development of the car vibration quality index using multiple linear regressions(MLR). A previous research related with automotive vibration quality used the method of calculating acceleration values of the point of a seat, a seat back, foot as RMS for objective evaluation. The automotive comfort is determined by RMS values. In comparison with the previous research, this study includes not only the vibration metrics, but also subjective values by jury evaluation. By indentifying the correlation between subjective evaluation and vibration metrics, the automotive vibration quality index is developed through MLR. Based on the results of this study, the proposed the automotive vibration quality index which developed through MLR will be helpful to obtain objective and reliable automotive comfort values.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.6
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• pp.123-134
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• 1999

Nowadays since the automobile is regarded as the third living space, comfortable conditions are required in the passenger compartment. The customer's concern on air-conditioning/heating, ventilation and demisting/defrosting performances has been much increased. Both ventilation and demisting /defrosting performances are directly influenced by register location, shape of regist guide vane, ventilation flow rate, air distribution , and air circulation pattern. Diffuse plume of air from the register is desirable not only to maintain comfort when the comfort when the comfortable condition has been satisfied but to improve demisting /defrosting performance. In this study, experimental and numerical investigation about the flow field of six different register vane types were carried out , respectively. The numerical analysis, based upon the $textsc{k}$-$\varepsilon$ turbulence model , was applied to the air flow field. The results show that the shape of register guide vane should be considered as an important design paramter.

• Journal of Power System Engineering
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• v.14 no.3
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• pp.33-38
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• 2010

Technology of vehicle industry has been developing and it is required a better vehicle performance than before. Therefore, the consumers are asking not only an economic efficiency, functionality, polished design, ride comfort and silence but also a driving stability. The ride comfort, silence and driving stability are influenced by the size of vehicle and various facilities. But the principal factor is a room noise and vibration sensed by a driver and passenger. Thus, the NVH of vehicle has been raised and used as a principal factor for evaluation of vehicle performance. The primary objective of this study is an optimized design of powertrain mounting system. To optimized design was applied MSC.Nastran optimization modules. Results of dynamic analysis for powertrain mounting system was investigated. By theses results, design variables was applied 12 dynamic spring constant. And the weighting factor according to translational displacement and rotational displacement applied 3 cases. The objective function was applied to minimize displacement of powertrain. And the design variable constraint was imposed dynamic spring constant ratio. The constraint of design variable for objective function was imposed bounce displacement for powertrain.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.683-688
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• 2012

Driver's feeling is variously affected by lots of components such as engine, frame, wheels, and seats during the operation of automobiles. The main objective of this research is to identify the correlation between subjective evaluation and vibration metrics that was set by ISO to investigate development of the car vibration quality index using multiple linear regressions (MLR). A previous research related with automotive vibration quality used the method of calculating acceleration values of the point of a seat, a seat back, foot as RMS for objective evaluation. The automotive comfort is determined by RMS values. In comparison with the previous research, this study includes not only the vibration metrics, but also subjective values by jury evaluation. By indentifying the correlation between subjective evaluation and vibration metrics, the automotive vibration quality index is developed through MLR. Based on the results of this study, the proposed the automotive vibration quality index which developed through MLR will be helpful to obtain objective and reliable automotive comfort values.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.101.5-101
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• 2002

A vehicle simulator is made here to simulate the lateral control of vehicles. Dead-reckoning sensors which consist of gyroscopes and accelerometers are utilized for the positioning of it. A significant side-slip occurs when the developed vehicle is drove autonomously. To cope with the side-slip, the vehicle is steered to follow the reference yaw rate which is generated by the relationship between the target point and the position of vehicle. The experimental results show the good performances of lane tracking and the passenger comfort.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.338-343
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• 2005

The Korean high speed train(KHST), developed since 1996, is presently undergoing commissioning tests on the high-speed track as well as on the conventional track since 2002. The purpose of the commissioning test is twofold: first to verify the performance of the train-set and equipments, and to demonstrate system reliability. Last December, KHST has reached the maximum speed of 350km/h and a number of data proving the performance of the train has been acquired. Among the data noise level and pressure variation in a cabin are important factors effecting passenger's comfort. Discussed in this paper are interior noise and pressure variation when the train passes tunnels during the 350km/h test.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1416-1423
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• 2007

Dynamic instability of the railway bridge can cause track irregularities and be directly connected with unstable passenger comfort and derailment of the train. Europe and Japan had studied on this problem for a long time since 1960's, Results of those studies are reflected in recent Eurocode and the bridge design code of Japanese railway bridges. However, even though some traffic safety requirements were applied in Kyoung-bu highspeed railway by French engineers, we experienced many difficulties from insufficient information of criteria background and application procedures. In this paper, a investigation of recent traffic safety requirements of Europe and Japan for railway bridges will be introduced and application procedures for the estimation of dynamic performance will be proposed.