• Title/Summary/Keyword: Frequency selective

Search Result 742, Processing Time 0.02 seconds

Critical Issues and Practical Strategies in Technology Education: Technology Education Practitioners' Perception in South Korea (기술교육의 쟁점과 실천 전략: 우리나라 기술교육 현장 전문가의 인식)

  • Sung, Eui-Suk;Kwon, Hyuk-Soo
    • 대한공업교육학회지
    • /
    • v.39 no.1
    • /
    • pp.189-208
    • /
    • 2014
  • The purpose of this research was to investigate the critical issues and practical strategies that Korean technology teachers perceived. To accomplish the purpose of this study, a qualitative study was conducted to identify critical issues and practical strategies of Korean technology education targeted on Korean technology teachers. A purposeful sampling for choosing technology teachers was used for this study with three selection conditions: 1) 'Excellent Korean technology teacher' award winning teachers, or 2) technology teachers actively involved in both on-line and off-line teachers' association, and 3) leaders in local technology teachers' association. This study conducted exploratory in-depth interviews with selective 15 technology teachers regarding critical issues and practical strategies of Korean technology teachers. The interpretation of the interview content was conducted by two researchers using the thematic analysis which analyzed the frequency of concepts, words, and meanings held from collected data. In the conclusion, critical issues researchers identified were 1) curriculum problems, 2) education environment and facilities problems, 3) teachers' problems, 4) students' problems, 5) related research institution and college problems, 6) social problems. Secondly, Korean technology teachers agreed with following practical strategies 1) separating technology education from home economic education, 2) sharing practices on managing and improving educational environment and laboratory for technology education, 3) actively involving in technology teachers' group, 4) motivating students using hands-on activity 5) improving the quality and the quantity on technology teachers preparatory institution, 6) advertising the values of technology education to the public. Lastly, the positive factors to succeed technology education were 1) technology education satisfying social needs and 2) technology teachers' will or passion toward improving their technology classrooms. The negative factors to hinder technology education were 1) low self-respect of Korean technology teachers and 2) rejection or retarded acceptance toward social transition. Several recommendations based the conclusion were suggested as 1) implementing supplementary study toward selected critical issues and 2) conducting exemplary case studies regarding concrete practical strategies for improving challenges of Korean technology education.

A Study of Current Perception Threshold of Trigeminal Nerve after Tooth Implantation (치아임플란트 시술 후 삼차신경에서의 전류인지역치에 대한 연구)

  • Lim, Hyun-Dae;Lee, Jung-Hyun;Lee, You-Mee
    • Journal of Oral Medicine and Pain
    • /
    • v.32 no.2
    • /
    • pp.187-200
    • /
    • 2007
  • This study attempted to contribute to the clinical application of implant operation by making a quantitative nerve examination using a neurometer for the evaluation of sensory disturbances that could be incurred after the implantation in the dental clinics, and it intended to establish an objective guideline in the evaluation of sensory nerve after the operation of implant. An inspection was performed with the frequencies of 2000Hz, 250 Hz and 5 Hz before and after the operations of tooth implant using $Neurometer^{(R)}$ CPT/C (Neurotron, Inc. Baltimore, Maryland, USA) for 44 patients who had performed an implant operation among the patients coming to Daejeon Sun Dental Hospital in 2006 and 30 people for control group. The measuring sites were maxillary nerve ending and mandibular nerve ending of trigeminal nerve according to the implant operating regions. The current perception threshold (CPT) by each nerve fiber was specifically responded under the electric stimulation of 2000 Hz in case of $A{\beta}$ fiber and of 250 Hz in case of $A{\delta}$ fiber and of 5Hz in case of C fiber. The CPT test could be performed to assess the damages of peripheral nerve in the trigeminal nerve area and it stimulated selective nerve fibers by generating the electricity of specific frequency in the peripheral nerve area. The nerve fibers with varied thickness were responsive selectively to the electric stimulation with different frequencies; accordingly, they applied the electric stimulation with different frequencies and the reaction threshold of $A{\beta},\;A{\delta}$ and C fibers selectively responsive to each electric current could be individually evaluated. In the assessment through the CPT, the increase and decrease of the CPT could be measured so that sensory disturbances such as hyperaesthesia or hypoaesthesia could be diagnosed. This study could obtain the following results after the assessment of the CPT before and after the implant operation. 1. In the assessment before and after the implant operation, the CPT in the frequencies of 2000 Hz, 250 Hz, 5 Hz for maxillary branch increased on the whole after the operation and the CPT for mandibular branch in the $A{\beta}$-fiber(2000 Hz) and C-fiber(5 Hz )after the operation increased statistically significantly. 2. For the groups of patients with medically compromised or its subsequent medicinal prescription, there were no significant differences before and after the implant operation and for the control groups, significantly high CPT was shown after the implant operation in the left $A{\beta}$-fiber(2000 Hz) and C-fiber(5 Hz). 3. In the comparison of the measured value of the CPT before the operation between the control group and the implant operation group, the latter group had a significantly high measured value of the CPT in the right $A{\beta}$-fiber(2000 Hz) and C-fiber(5 Hz) and there were significant differences in $A{\beta}$-fiber(2000 Hz) in the CPT assessment after the implant operation for the control group. 4. Male participants had higher CPT than female counterparts; however, there were no statistic significances. In the CPT evaluation before and after implant operation, there were no statistical differences in the male group while the right C-fiber(5 Hz) and left $A{\beta}$-fiber(2000Hz) were significantly high in the female group. 5. In the comparison between the group who complain sensory disturbance and the other group, the CPT increased on the whole in the former group, but there were no statistical significances. In the groups, whom there was an increase in VAS, the CPT after the implant operation in the right C-fiber(5 Hz) increased significantly; meanwhile, in case that the VAS mark was '0' before and after the operation, the CPT after the operation in the left $A{\beta}$-fiber(2000 Hz) increased significantly. This study suggested that the CPT measurements using $Neurometer^{(R)}$ CPT/C, provide useful information of objective and quantitative sensory disturbances for tooth implantation.