• 제목/요약/키워드: POSITION CHARACTERISTICS

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비례솔레노이드 액추에이터를 이용한 압력제어밸브 (Pressure Control Valve using Proportional Electro-magnetic Solenoid Actuator)

  • 함영복;박평원;윤소남
    • 대한기계학회논문집A
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    • 제30권10호
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    • pp.1202-1208
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    • 2006
  • This paper presents an experimental characteristics of electro-hydraulic proportional pressure control valve. In this study, poppet and valve body which are assembled into the proportional solenoid were designed and manufactured. The constant force characteristics of proportional solenoid actuator in the control region should be independent of the plunger position in order to be used to control the valve position in the fluid flow control system. The stroke-force characteristics of the proportional solenoid actuator is determined by the shape (or parameters) of the control cone. In this paper, steady state and transient characteristics of the solenoid actuator for electro-hydraulic proportional valve are analyzed using finite element method and it is confirmed that the proportional solenoid actuator has a constant attraction force in the control region independently on the stroke position. The effects of the parameters such as control cone length, thickness and taper length are also discussed.

Cone-beam computed tomographic evaluation of the temporomandibular joint and dental characteristics of patients with Class II subdivision malocclusion and asymmetry

  • Huang, Mingna;Hu, Yun;Yu, Jinfeng;Sun, Jicheng;Ming, Ye;Zheng, Leilei
    • 대한치과교정학회지
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    • 제47권5호
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    • pp.277-288
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    • 2017
  • Objective: Treating Class II subdivision malocclusion with asymmetry has been a challenge for orthodontists because of the complicated characteristics of asymmetry. This study aimed to explore the characteristics of dental and skeletal asymmetry in Class II subdivision malocclusion, and to assess the relationship between the condyle-glenoid fossa and first molar. Methods: Cone-beam computed tomographic images of 32 patients with Class II subdivision malocclusion were three-dimensionally reconstructed using the Mimics software. Forty-five anatomic landmarks on the reconstructed structures were selected and 27 linear and angular measurements were performed. Paired-samples t-tests were used to compare the average differences between the Class I and Class II sides; Pearson correlation coefficient (r) was used for analyzing the linear association. Results: The faciolingual crown angulation of the mandibular first molar (p < 0.05), sagittal position of the maxillary and mandibular first molars (p < 0.01), condylar head height (p < 0.01), condylar process height (p < 0.05), and angle of the posterior wall of the articular tubercle and coronal position of the glenoid fossa (p < 0.01) were significantly different between the two sides. The morphology and position of the condyle-glenoid fossa significantly correlated with the three-dimensional changes in the first molar. Conclusions: Asymmetry in the sagittal position of the maxillary and mandibular first molars between the two sides and significant lingual inclination of the mandibular first molar on the Class II side were the dental characteristics of Class II subdivision malocclusion. Condylar morphology and glenoid fossa position asymmetries were the major components of skeletal asymmetry and were well correlated with the three-dimensional position of the first molar.

한국경찰의 개방형임용제 도입가능성에 대한 검토 (Review on Introduction Possibility of Open Position System in Korea Police)

  • 조현빈
    • 한국콘텐츠학회논문지
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    • 제11권2호
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    • pp.397-407
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    • 2011
  • 개방형 직위제도는 기존의 계급 및 계층제 중심의 조직관리 형식에서 탈피하여 직무수행의 성격에 따라 직위에 대한 적합한 직무수행요건을 충족하는 외부인사를 활용하는 제도로서 일종의 직무중심의 직위분류제적 성격을 내포하는 제도이다. 1999년부터 정부부처의 1-3급 고위공무원을 임용하고 있으며 그 활용 범위가 점차 확대되고 있다. 그러나 경찰과 같이 직무의 성격이 타 공직조직과 달리 특수한 환경을 가지고 있는 경우에는 일반적인 개방형직위제도를 그대로 활용할 수 있는가에 대한 논란이 있다. 경찰조직에서는 책임운영기관인 운전면허시검관리단, 경찰청 감사관, 경찰병원장 등을 개방형 직위제로 운영하고 있을 뿐이다. 이와 관련하여 개방형직위제도의 장점을 경찰조직에서 더욱 확대할 수 있는 방안을 모색하고자 한다.

정상유동 장치에서 유동 특성 평가 방법에 대한 연구(4) - 유속분포(2) (Study on Evaluation Method of Flow Characteristics in Steady Flow Bench(4) - Velocity Profile(2))

  • 박찬준;성재용;엄인용
    • 한국자동차공학회논문집
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    • 제24권2호
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    • pp.242-254
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    • 2016
  • This paper is the forth investigation on the evaluation methods of flow characteristics in a steady flow bench. In the previous works, it was concluded that the assumption of the solid rotation might cause serious problems and both of the eccentricity and the velocity profile distort the flow characteristics when using the ISM at 1.75B plane. Also particle image velocimetry (PIV) measurement at this position showed that the real velocity profile was far from the assumption of ISM evaluation. In this paper, the planar velocity profiles were measure from 1.75B to 6.00B position by PIV and the characteristics were examined according to the valve angles and lifts for further investigations about the effect of the position on the velocity profile. The results show that $26^{\circ}$ valve angle is always an unique exceptional case in all aspects. If the valve angle is $21^{\circ}$ and below, the planar velocity profiles according to the lift and the position are similar to each other, however, the tangential velocity curves along with the radial direction have common tendencies up to $16^{\circ}$ angle. Also the well arranged swirl behaviors are generally observed at the position above 3.00B and the velocity contour lines come closer to the concentric circle as the valve lift increases. In addition, the gradient of tangential velocity along with the radial direction from the swirl center becomes stable and constant as the position goes downstream. Concurrently the velocity gradient is larger to the eccentric direction of the center. In the meantime the tangential velocity curves along with the radial direction are irregular and various at 1.75B, however, they become regular and reach higher level as the evaluation position goes downstream. At this time the curves of 4.50B are the best fitted to the ideal one. On the other hand in an exceptional case, $26^{\circ}$, the velocity contours are very complicated over 6mm valve lift regardless the position and the gradient increases to the opposite direction of the eccentric center. Also, 6.00B is a best fitting position in the geometrical cylinder center base. With respect to the swirl center, the distribution range of centers for 1.75B is different to that for the other positions and the eccentricities of this plane are larger regardless the valve angle. After 1.75B, there is no certain tendency in the center position change according to the valve angle and lift. Additionally, the eccentricities are not sufficiently small to neglecting the effect on ISM measurement.

과잉 감쇠 반응을 나타내는 전기 유압식 서어보 (Position control of the overdamped electrohydraulic servosystem)

  • 송창섭;박태규;김세창
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 16-17 Oct. 1987
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    • pp.340-345
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    • 1987
  • This paper is describes the improvement of the transient response of the electrohydraulic position control system which exhibit the over-damped characteristics. A new approach, Position Error Prefiltered Proportional (PEPP) control, is proposed and the computer simulation results for the transient responses are analyzed. Experimental results using Z-80 microprocessor are presented.

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기능적 조음장애아동과 일반아동의 어중자음 연쇄조건에서 나타나는 어중종성 오류 특성 비교 (Comparison of error characteristics of final consonant at word-medial position between children with functional articulation disorder and normal children)

  • 이란;이은주
    • 말소리와 음성과학
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    • 제7권2호
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    • pp.19-28
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    • 2015
  • This study investigated final consonant error characteristics at word-medial position in children with functional articulation disorder. Data was collected from 11 children with functional articulation and 11 normal children, ages 4 to 5. The speech samples were collected from a naming test. Seventy-five words with every possible bi-consonants matrix at the word-medial position were used. The results of this study were as follows : First, percentage of correct word-medial final consonants of functional articulation disorder was lower than normal children. Second, there were significant differences between two groups in omission, substitution and assimilation error. Children with functional articulation disorder showed a high frequency of omission and regressive assimilation error, especially alveolarization in regressive assimilation error most. However, normal children showed a high frequency of regressive assimilation error, especially bilabialization in regressive assimilation error most. Finally, the results of error analysis according to articulation manner, articulation place and phonation type of consonants of initial consonant at word-medial, both functional articulation disorder and normal children showed a high error rate in stop sound-stop sound condition. The error rate of final consonant at word-medial position was high when initial consonant at word-medial position was alveolar sound and alveopalatal sound. Futhermore, when initial sounds were fortis and aspirated sounds, more errors occurred than linis sound was initial sound. The results of this study provided practical error characteristics of final consonant at word-medial position in children with speech sound disorder.

Characteristics of shoulder pain, muscle tone and isokinetic muscle function according to the scapular position of elite boxers

  • Lee, Ju-Hong;Kim, Ho;Shin, Won-Seob
    • Physical Therapy Rehabilitation Science
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    • 제9권2호
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    • pp.98-104
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    • 2020
  • Objective: The shoulders are a particularly an important body part for elite boxers. The purpose of this study was to investigate the characteristics of the upper trapezius (UT), infraspinatus (IS) muscle tone, pain, and isokinetic muscle function of shoulder movements such as external rotation, internal rotation, protraction, and retraction according to the scapular position of elite boxers of the Korean national team. Design: Cross-sectional study. Methods: Using the double square method, the scapular position was measured and divided into the forward scapular position group (n=8) with a measurement distance of 135 mm or more, and the normal scapular position group (n=10) with a measurement distance of less than 135 mm. Through the numeric rating scale of the subject, the pain value displayed during movement was measured. The muscle tone of the subjects' UT and IS were measured. The isokinetic muscle function of ER, IR, protraction, and retraction were measured using isokinetic exercise equipment. Results: The results of this study showed statistically significant differences when comparing muscle tone of the UT and IS, shoulder pain, isokinetic function of ER and IR, protraction, and retraction according to scapular position (p<0.05). Conclusions: The findings of this study were that shoulder muscle tone, pain, and isokinetic muscle function were affected according to the scapular position of elite boxers. In the future, this information may be a useful indicator when studying the effects of medium and long-term intervention in elite boxers who possess these characteristics.

A Position Sensorless Control System of SRM over Wide Speed Range

  • Baik, Won-Sik
    • 조명전기설비학회논문지
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    • 제22권3호
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    • pp.66-73
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    • 2008
  • This paper presents a position sensorless control system of SRM over wide speed range. Due to the doubly salient structure of the SRM, the phase inductance varies along with the rotor position. Most of the sensorless control techniques are based on the fact that the magnetic status of the SRM is a function of the angular rotor position. The rotor position estimation of the SRM is somewhat difficult because of its highly nonlinear magnetizing characteristics. In order to estimate more accurate rotor position over wide speed range, Neural Network is used for this highly nonlinear function approximation. Magnetizing data patterns of the prototype 1-hp SRM are obtained from locked rotor test, and used for the Neural Network training data set. Through measurement of the flux-linkage and phase currents, rotor position is able to estimate from current-flux-rotor position lookup table which is constructed from trained Neural Network. Experimental results for a 1-hp SRM over 16:1 speed range are presented for the verification of the proposed sensorless control algorithm.

정상 신생아의 체위에 따른 수면양상 및 행동변화 비교 (The Comparison of Sleep Characteristics According to the Sleep Positions in Healthy Newborns)

  • 이애란;안혜영;이종순
    • Child Health Nursing Research
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    • 제5권3호
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    • pp.281-291
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    • 1999
  • The purpose of this study was to compare the sleep characteristics between the prone and the supine position in healthy newborns. The 48 newborns were observed in the prone position and the supine position respectively on the 2nd day after birth. The data were collected from January to May, 1999. The state of a newborn was classified and categorized to 6 states (deep sleep. light sleep, drowsy, quiet alert, active alert, crying) by Barnard. The movements of eyes, face and extremities, pulse and arterial oxygen were observed and recorded continuously from the start of sleep after feeding until the time of being woken for the next feeding by a trained nurse The data was analyzed by using paired t-test. The results of this study were as follows; 1. There was no significant difference in the length of sleeping time between the prone and the supine position. 2. There was no significant difference in the length and frequencies of each states(deep sleep, light sleep, drowsy, quiet alert, active alert, crying) between the prone and the supine position But the frequency of light sleep in the supine position was significantly higher than that of the prone position. 3 There was no significant difference In the numbers or eyes movements between the prone and the supine sleep position. But the amount of facial and extremity movement in the supine position was significantly higher than those in the prone position 4. There was no significant difference in the arterial oxygen content between the prone and the supine sleep position. 5. There was no significant difference in the heart rates between the prone and the supine sleep position. The above results indicated that the newborns in the prone Position moved less and slept deeper than those in the supine position. though there was no difference in the length of sleep or arterial oxygen content between the prone and the supine sleep Position. But. Nurses and mothers should consider the relationship between the sleep Position and SIDS suggested by previous researches. The infant's 'awakening' during sleep is a normal process and rather valuable because it can provide an opportunity to promote a stronger relationship between mother and baby. So, It is suggested that the supine sleep position is better than the prone sleep position for infants.

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방사성 추적자를 이용한 피스톤의 비정상 온도 특성에 관한 연구 -피스톤 링 갭 위치와 블로우 바이 가스의 영향- (The Investigations of the Characteristics of Unsteady Piston Temperature Using Radiotracers-The Effect of Piston Ring Gap Position and Blow By Gas)

  • 김중수;김승일;민병순;박승일;오대윤;정성희;진준하
    • 한국자동차공학회논문집
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    • 제8권4호
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    • pp.1-9
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    • 2000
  • To understand the thermal characteristics around the piston ring gap ring gap positions and piston temperatures are measured simultaneously. The locations of piston ring gap are measured by the radio-tracer method and piston temperature are measured by a K-type thermocouple and scissors type linkage system. From these experiments following facts are clarified. Piston temperatures fluctuate according to the piston ring rotation. And the temperature fluctuation is mainly affected by top ring gap position irrelevant to the second ring fop position. If the top ring gap position increases and the temperature of top ring groove shows maximum value when top rin gap position coincide with temperature measuring point. The maximum amplitude of temperature fluctuation which is proportional to the blow by gas rate is around 12-15$^{\circ}C$.

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