An Integrated Model of Static and Dynamic Measurement for Seat Discomfort

Dian Darina Indah Daruis,Baba Md Deros,Mohd Jailani Mohd Nor,Mohammad Hosseini 대한산업공학회 2011 Industrial Engineeering & Management Systems Vol.10 No.3

A driver interacts directly with the car seat at all times. There are ergonomic characteristics that have to be followed to produce comfortable seats. However, most of previous researches focused on either static or dynamic condition only. In addition, research on car seat development is critically lacking although Malaysia herself manufactures its own car. Hence, this paper integrates objective measurements and subjective evaluation to predict seat discomfort. The objective measurements consider both static and dynamic conditions. Steven"s psychophysics power law has been used in which after expansion; ψ = a+bφs<SUP>α</SUP>+cφv<SUP>β</SUP> where ψ is discomfort sensation, φs<SUP>α</SUP> is static modality with exponent α and φv<SUP>β</SUP> is dynamic modality with exponent β. The subjects in this study were local and the cars used were Malaysian made compact car. Static objective measurement was the seat pressure distribution measurement. The experiment was carried out on the driver"s seat in a real car with the engine turned off. Meanwhile, the dynamic objective measurement was carried out in a moving car on real roads. During pressure distribution and vibration transmissibility experiments, subjects were requested to evaluate their discomfort levels using vehicle seat discomfort survey questionnaire together with body map diagram. From subjective evaluations, seat pressure and vibration dose values exponent for static modality α=1.51 and exponent for dynamic modality β=1.24 were produced. The curves produced from the Eq.s showed better R-sq values (99%) when both static and dynamic modalities were considered together as compared to Eq. with single modality only (static or dynamic only R-Sq = 95%). In conclusion, car seat discomfort prediction gives better result when seat development considered both static and dynamic modalities; and using ergonomic approach.

An Integrated Model of Static and Dynamic Measurement for Seat Discomfort

Daruis, Dian Darina Indah,Deros, Baba Md,Nor, Mohd Jailani Mohd,Hosseini, Mohammad Korean Institute of Industrial Engineers 2011 Industrial Engineeering & Management Systems Vol.10 No.3

A driver interacts directly with the car seat at all times. There are ergonomic characteristics that have to be followed to produce comfortable seats. However, most of previous researches focused on either static or dynamic condition only. In addition, research on car seat development is critically lacking although Malaysia herself manufactures its own car. Hence, this paper integrates objective measurements and subjective evaluation to predict seat discomfort. The objective measurements consider both static and dynamic conditions. Steven's psychophysics power law has been used in which after expansion; ${\psi}\;=\;a+b{\varphi}_s^{\alpha}+c{\varphi}_v^{\beta}$ where ${\psi}$ is discomfort sensation, ${\varphi}_s^{\alpha}$ is static modality with exponent ${\alpha}$ and ${\varphi}_v^{\beta}$ is dynamic modality with exponent ${\beta}$. The subjects in this study were local and the cars used were Malaysian made compact car. Static objective measurement was the seat pressure distribution measurement. The experiment was carried out on the driver's seat in a real car with the engine turned off. Meanwhile, the dynamic objective measurement was carried out in a moving car on real roads. During pressure distribution and vibration transmissibility experiments, subjects were requested to evaluate their discomfort levels using vehicle seat discomfort survey questionnaire together with body map diagram. From subjective evaluations, seat pressure and vibration dose values exponent for static modality ${\alpha}$ = 1.51 and exponent for dynamic modality ${\beta}$ = 1.24 were produced. The curves produced from the $E_{q.s}$ showed better $R_{-sq}$ values (99%) when both static and dynamic modalities were considered together as compared to Eq. with single modality only (static or dynamic only R-Sq = 95%). In conclusion, car seat discomfort prediction gives better result when seat development considered both static and dynamic modalities; and using ergonomic approach.

조명 조건에 강건한 스마트폰 카메라 맥박 측정을 위한 다이내믹 레인지 재구성 알고리즘

박상욱,차경래 대한임베디드공학회 2015 대한임베디드공학회논문지 Vol.10 No.1

Recently, handy pulse measurement method was introduced by using smart phone camera. However, measured values are not consistent with the variations of external light conditions, because the external light interfere with dynamic range of captured pulse image. Thus, adaptive dynamic range reconstruction algorithm is proposed to conduct pulse measurement robust to light condition. The minimum and maximum values for dynamic ranges of green and blue channels are adjusted to appropriate values for pulse measurement. In addition, sigmoid function based curve is applied to adjusted dynamic range. Experimental results show that the proposed algorithm conducts suitably dynamic range reconstruction of pulse image for the interference of external light sources.

Analysis, Modeling and Compensation of Dynamic Imbalance Error for a Magnetically Suspended Sensitive Gyroscope

Xin Chaojun,Cai Yuanwen,Ren Yuan,Fan Yahong,Xu Guofeng,Lei Xu 한국자기학회 2016 Journal of Magnetics Vol.21 No.4

Magnetically suspended sensitive gyroscopes (MSSGs) provide an interesting alternative for achieving precious attitude angular measurement. To effectively reduce the measurement error caused by dynamic imbalance, this paper proposes a novel compensation method based on analysis and modeling of the error for a MSSG. Firstly, the angular velocity measurement principle of the MSSG is described. Then the analytical model of dynamic imbalance error has been established by solving the complex coefficient differential dynamic equations of the rotor. The generation mechanism and changing regularity of the dynamic imbalance error have been revealed. Next, a compensation method is designed to compensate the dynamic imbalance error and improve the measurement accuracy of the MSSG. The common issues caused by dynamic imbalance can be effectively resolved by the proposed method in gyroscopes with a levitating rotor. Comparative simulation results before and after compensation have verified the effectiveness and superiority of the proposed compensation method.

실물실험을 통한 다이나믹 유량밸런싱 적용 공동주택 세대의 에너지소비량 평가

류성룡(Seong-Ryong Ryu),정창헌(Chang-Heon Cheong),조현(Hyun Cho) 한국지열·수열에너지학회 2016 한국지열에너지학회논문집 Vol.12 No.4

Even though the control device of the heating system works well, insufficient water flow rates can degrade control performance and thermal comfort. The water flow rate should be adjusted appropriately to cope with the heating load of each zone. In order to solve these problems, a new balancing concept "dynamic balancing" was proposed where a balancing valve opening can be automatically modulated according to the heating condition of the room. This study analyzed the effects of dynamic balancing upon indoor thermal environment and energy consumption in a radiant floor heating system through field measurement. Under part-load conditions, the use of a dynamic balancing is a more effective method to reduce energy consumption and to prevent a cavitation. Dynamic balancing is able to help boost the temperature of a room in the start-up period.

Measures for the Characterization of Dynamic States of Dynamical Systems

김영태 한국물리학회 2014 새물리 Vol.64 No.1

Dynamical systems whose equations of motion are expressed as a set of ordinary differential equations show various dynamic states: stationary states, periodic states, quasiperiodic states, chaotic states, strange non-chaotic states, etc. While the natures of some of those states can be confirmed easily by visual inspection the natures of other states cannot be confirmed without special measures. Therefore, these measures are essential in any bifurcation analyses of dynamical systems. In this paper, important qualitative and quantitative measures used for characterizing dynamic states are reviewed.

Design and Application of Two-Stage Performance Measurement System Considering Dynamic Capabilities

Sun-Man Kwon(권순만),Chang Hee Han(한창희) 한국산업경영시스템학회 2018 한국산업경영시스템학회지 Vol.41 No.2

The dynamic capabilities of sensing market signals, creating new opportunities and reconfiguring resources and capabilities to new opportunities in a rapidly changing economic environment determines the competitiveness of the enterprise to create added value and survival. This study conceptualized a two-stage performance measurement framework based on the casual model of resource (input)-process-performance (output). We have developed a ‘Process capability index’ that reflect the dynamic capabilities factors as a key intermediary product linking resource inputs and performance outputs in enterprise performance measurement. The process capability index consists of four elements : manpower (level of human resource), operation productivity, structure and risk management. The DEA (Data Envelopment Analysis) model was applied to the developed performance indicators to analyze the branch office performance of a telecom company. Process capability efficiency (stage 1) uses resource inputs to reach a certain level of process capabilities. In performance result efficiency (stage 2), the process capabilities are used to generate sales revenues and subscribers. The two-stage DEA model derives intermediate output values that optimize the individual stages simultaneously. Some branch offices in the telecom company have focused on process capability efficiency or some other branch offices focused on performance result efficiency. Positioning map using two-stage efficiency decomposition and benchmarking can help identify the sources of inefficiencies and visualize strategic directions for performance optimization. Applications of two-stage DEA in conjunction with the case study that are meaningfully used in performance measurement areas have been scarce. In particular, this paper has the contribution to present a new performance measurement model considering the organization theory, the dynamic capabilities.

조명 변화에 따른 조절과 동공크기의 동적 측정

박형민,성덕용,추병선 대한시과학회 2019 대한시과학회지 Vol.21 No.4

Purpose : This study investigated the dynamic measurement of accommodation response and pupil size change by different lighting conditions and its effect on visual function. Methods : Seventeen (23.06±0.51) students participated who had no history of ocular surgery. All participants had normal binocular vision and more than 0.8 visual acuity. Dynamic accommodation and pupil size were measured using open-type auto-refractor(WAM-5500) with 5 Hz frequency under three lighting conditions (photopic vision, mesopic vision, and scotopic vision). Accommodation stimulus in the distance of 40 cm, 40~30 cm, 30 cm, 30~20 cm, and 20 cm were induced for 5 seconds. In addition, the visual function such as VA and contrast sensitivity were measured. Results : The accommodation response was the highest in photopic vision and the lowest in scotopic vision(p<0.050). The change of pupil size was measured to be the smallest under photopic vision and the largest under scotopic vision(p<0.050). The visual acuity and contrast sensitivity also showed the highest value in photopic vision and the lowest value in scotopic vision(p<0.050). Conclusion : This study demonstrated the dynamic changes of accommodation and pupil size under different lighting conditions. Under low lighting condition, accommodative response were less than accommodative stimulus and visual function deteriorated accordingly. It showed continuous changes of accommodation under static condition, therefore several measurement of accommodation or visual function may be recommend. 목적 : 본 연구에서는 각기 다른 조명에서 조절반응과 동공의 크기 측정을 동적으로 하고 그에 따른 조절과 동공의 동적 변화가 시기능에 어떠한 영향을 미치는지 알아보고자 하였다. 방법 : 연구대상은 안과적 수술 경력이 없는 17명(23.06±0.51세)을 대상으로 하였고 기본검사를 통해 나안시력이 0.8 이상인 인원을 대상자로 선정하였다. 3개의 조명 조건(명소시, 박명시, 암소시)에서 개방형 자동굴절검사기(WAM-5500)를 통해 5 Hz로 조절 및 동공크기를 동적으로 측정하였으며 조절자극은 40 cm, 40~30 cm,30 cm, 30∼20 cm, 20 cm에서 5초간 주었다. 더불어 원거리 시력 및 대비감도를 측정하였다. 결과 : 명소시 상태에서 조절반응량이 가장 높았으며 암소시 상태에서 조절반응량이 가장 낮게 나타났다(p<0.050). 동공의 크기 변화는 명소시 상태에서 동공의 크기가 가장 작게 측정되었고, 암소시 상태에서 동공 크기가 가장 크게 측정되었다(p<0.050). 시력과 대비감도에서도 명소시 상태에서 모두 가장 높은 수치를 나타냈으며,암소시 상태에서 시력과 대비감도 모두 가장 낮게 측정되었다(p<0.050). 결론 : 본 연구의 결과로 다른 조명 조건하에서 조절자극이 변화될 때 조절반응량과 동공크기가 연속적으로 변화됨을 알 수 있었다. 낮은 조도에서 조절반응량은 조절자극보다 낮게 나타났고 시력 및 대비감도 모두 저하되었다. 이것은 정적인 상태에서도 조절의 지속적인 변화를 나타낸다. 그러므로 조절 또는 시기능 검사 시 동적 측정이 필요할 것으로 사료된다.

내단열 콘크리트 벽체의 현장 측정을 통한 비정상상태의 열적 거동특성 평가

문지훈,이예지,고명진 한국생활환경학회 2022 한국생활환경학회지 Vol.29 No.2

This study analyzes the decrement factor among the dynamic thermal behavior of a complete building component in a non-steady-state for a highly insulated concrete wall constructed with internal insulation. As a method of calculating the decrement factor, there is a theoretical calculation method according to ISO 13786 and in-situ measurement. The measurement period was summer, and compared environment parameters with previous studies, it is evaluated that the obtained environment data is similar during the measurement period. The decrement factor based on in-situ measurements is 0.053 to 0.202. On the other side, the decrement factor calculated by ISO 13786 is 0.329. The deviation between the two values is 223.6% on average, and in this deviation is reasonable when compared with previous studies. The cause of these results is decrement factor according to the in-situ measurement is affected by the external environment, such as solar radiation.

Effect of excitation type on dynamic system parameters of a reinforced concrete bridge

Wahab, M.M. Abdel,De Roeck, G. Techno-Press 1999 Structural Engineering and Mechanics, An Int'l Jou Vol.7 No.4

Damage detection in civil engineering structures using the change in dynamic system parameters has gained a lot of scientific interest during the last decade. By repeating a dynamic test on a structure after a certain time of use, the change in modal parameters can be used to quantify and qualify damages. To be able to use the modal parameters confidentially for damage evaluation, the effect of other parameters such as excitation type, ambient conditions,... should be considered. In this paper, the influence of excitation type on the dynamic system parameters of a highway prestressed concrete bridge is investigated. The bridge, B13, lies between the villages Vilvoorde and Melsbroek and crosses the highway E19 between Brussels and Antwerpen in Belgium. A drop weight and ambient vibration are used to excite the bridge and the response at selected points is recorded. A finite element model is constructed to support and verify the dynamic measurements. It is found that the difference between the natural frequencies measured using impact weight and ambient vibration is in general less than 1%.