소결 온도에 따른 0.98(Na_0.5K_0.5)NbO₃-0.02Li(Sb_0.17Ta_0.83)O₃+0.01wt%ZnO 세라믹스의 압전 특성

이동현,이승환,이성갑,이규탁,이영희,Lee, Dong-Hyun,Lee, Seung-Hwan,Lee, Sung-Gap,Lee, Ku-Tak,Lee, Young-Hie 한국전기전자재료학회 2011 전기전자재료학회논문지 Vol.24 No.7

We studied sintering temperature to enhance the piezoelectric properties of $0.98(Na_{0.5}K_{0.5})NbO_3-0.02Li(Sb_{0.17}Ta_{0.83})O_3$+0.01wt%ZnO (hereafter NKN-LST+ZnO) lead free piezoelectric ceramics. The synthesis and sintering method were the conventional solid state reaction method and sintering was executed at $1,080\sim1,120^{\circ}C$. We found that NKN-LST+ZnO ceramics at optimal sintering temperature showed the improved piezoelectric properties at the optimal sintering temperature. The NKN-LST+ZnO ceramics show good performance with piezoelectric constant $d_{33}$= 153 pC/N sintered at $1,090^{\circ}C$. The results reveal that NKN-LST+ZnO ceramics are promising candidate materials for lead-free piezoelectric application.

하악 전돌증 환자에서 전산화 단층 촬영을 이용한 하악관의 해부학적 위치에 관한 연구

이동현,김재원,이수연,김재현,안상헌,이상한,장현중,Lee, Dong-Hyun,Kim, Jae-Won,Lee, Su-Youn,Kim, Jae-Hyun,An, Sang-Heon,Lee, Sang-Han,Jang, Hyun-Jung 대한악안면성형재건외과학회 2009 Maxillofacial Plastic Reconstructive Surgery Vol.31 No.6

Purpose: In this study, we analyzed and compared the anatomical position of the mandibular canal in normal occlusion and mandibular prognathism patients. Patients and Methods: Computed tomography image from 58 patients were divided into normal occlusion group and mandibular prognathism group, and each measurement were taken in the each measuring points(2nd premolar, 1st molar, 2nd molar, 3rd molar, ramus). Measurements were statistically analyzed by student's t-test. Results: BC (Thickness of the buccal cortex) value was 2.3~2.7 mm, CB (Distance from the canal to the lingual aspect of the buccal cortex) value was 1.3~4.3 mm, MC (Diameter of the canal) value was 3.2~3.8 mm, LI (Distance from the canal to the lingual aspect of the lingual cortex) value was 2.0~3.7 mm, TM (Thickness of the total mandible) value was 9.5~12.9 mm and CM (Distance from the canal to the inferior border of the mandible) value was 6.9~17.5 mm. Conclusion: In the comparison between two groups, there was statistically significant difference in CB value of 2nd, 3rd molar between normal occlusion and mandibular prognathism, and other value in the rest of the measuring points didn't show statistically significant difference.

대학 공시정보를 활용한 교육국제화역량 인증 여부 예측: 이산선택모형에 의한 대학알리미 공시정보 분석

이동현(Lee, Dong-hyun),조순정(Cho, Soon-jeong) 한국경영교육학회 2020 경영교육연구 Vol.35 No.3

[연구목적] 본 연구는 대학 공시정보를 활용하여 교육국제화역량 인증(IEQAS) 여부를 예측하며, 대학의 인증 유지를 위한 자가 점검에 적합한지 연구 모형을 검증하는데 목적이 있다. [연구방법] 동 연구는 IEQAS 인증․미인증 예측을 위해 2019년 대학알리미 웹사이트에 공개된 138개 사립 대학의 공시정보를 수집했다. 이어, 인증 대학 77개교 및 미인증 대학 61개교 두 집단 간 지표 차이를 검정 후, 5개의 대학경쟁력지표 및 9개의 재정회계지표를 독립 변수로, 2019년 3월에 발표된 IEQAS 인증 결과를 이산형 종속 변수로 설정하여 이산선택모형에 따라 로짓분석과 판별분석을 하였다. [연구결과] 본 연구자들은 t-검정으로 선별한 재학생충원율/신입생충원율/전임교원확보율(이상 대학경쟁력), 학생1인당교육비/교육비환원율/부채비율/법인전임급비율(이상 재정회계)을 연구 모형에 유의한 요인으로 투입했다. 그 결과, 대학경쟁력 지표를 통한 예측력은 로짓분석 71.7%, 판별분석 71.0%로, 재정회계 지표의 경우 로짓분석 70.3%, 판별분석 66.7%의 예측력을 보였다. 동 이산선택모형 내에 공통으로 관여한 유의미한 변수는 재학생충원율, 신입생충원율과 학생1인당교육비로 나타났다. [연구의 시사점] 동 연구는 조직의 부실 여부 예측에 유용한 로짓분석과 판별분석을, 정부의 대학별 공개 자료를 활용하여 IEQAS 인증․미인증 예측에 적용해 본 가치를 지닌다. 본 연구의 이산선택모형은 타당성과 신뢰성이 확인됨으로써, 대학이 손수 IEQAS 인증 유지 점검 시 활용할 수 있으며 대학 평가에 관한 경영교육 실무에 기여할 것이다. [Purpose] Based on a discrete choice model(DCM), this study aims to predict the ‘pass/fail’ of the International Education Quality Assurance (IEQAS) by analyzing publicly opened dataset. Thus, it will enable Korean universities to self-test their IEQAS-related capabilities in a productive manner. [Methodology] This work utilized disclosed data on academyinfo.go.kr in 2019, including a total of 138 private universities from My university competitiveness(MUC), Financial accounting index(FAI); relying on related literature, it proposed two hypotheses and 14 independent variables, followed by conducting logit analysis(LA) and discriminant analysis(DA). [Findings] First, t-tests identified three MUC variables(Levy with enrolled students; Levy with new students; Faculty in full service) and four FAI variables(Educational expenditure; Educational restitution rate; Liability ratio; Corporate transferred money) between 77 IEQAS ‘pass’ group and 61 IEQAS ‘fail’ group in 2019. This DCM presented the following predictive powers: 71.7%-LA vs 71.0%-DA in MUC and 70.3% -LA vs 66.7%-DA in FAI, while Levy with enrolled students, Levy with new students and Educational expenditure worked as keys to predicting the ‘pass/fail’. [Implications] The DCM combining LA/DA can be used for both scholars on the business education area and the IEQAS-related practitioners.

광대역 파장가변 이중 링 공진기 Add/Drop 필터

이동현,이태형,박준오,김수현,정영철,Lee, Dong-Hyun,Lee, Tae-Hyung,Park, Joon-Oh,Kim, Su-Hyun,Chung, Young-Chul 한국광학회 2007 한국광학회지 Vol.18 No.3

본 논문에서는 굴절률 차이가 큰 폴리머 광 도파로를 이용하여 광대역 파장가변이 가능한 이중 링 공진기 Add/Drop 필터를 제작하였다. Add/Drop 필터의 제작시 공정 오차에 둔감한 특성을 갖도록 광 결합기를 설계하였다. 코어와 클래딩의 굴절률은 1550 nm 파장 대역에서 각각 1.51, 1.378로 약 $100{\mu}m$ 정도의 곡률 반경을 가지는 곡선 도파로를 수용할 수 있다. 두 개의 링이 동시에 공진하는 파장 대역에서 Drop 특성은 이웃하는 피크 좌다 약 2.9 dB 이상 높은 특성을 보였다. 이 필터는 반사형 반도체 광증폭기 등과의 하이브리드 집적을 통하여 광대역 파장 가변 레이저 다이오드를 구현하는데 활용할 수 있을 것으로 기대된다. A widely tunable add/drop filter composed of double ring resonators is implemented with high-index-contrast polymer waveguide. To enhance the productivity, directional couplers are designed to have good fabrication tolerance. The refractive indices of the core and cladding in the 1550 nm wavelength are 1.51 and 1.378, respectively. Drop response in comparison with neighborhood peak gets enhanced by more than 2.9 dB at the wavelength where both rings resonate. This filter can be used to build widely tunable laser diode through hybrid-integration with reflective SOA.

견인요법(牽引療法)을 병용한 요통(腰痛) 및 요각통(腰脚痛) 환자 40례(例)의 임상적 고찰

이동현,박은주,신정철,나건호,위통순,이삼로,류충열,조명래,채우석,윤여충,Lee, Dong-hyun,Park, Eun-ju,Shin, Jung-chul,Na, Gun-ho,Wei, Tung-shuen,Lee, Sam-ro,Lyu, Chung-yeol,Cho, Myung-rae,Chae, Wu-suk,Yoon, Yeo-choong 대한침구의학회 2004 대한침구의학회지 Vol.21 No.5

Objectives : The purpose of this report is to use more Traction treatment clinically by comparing th Improvement of Low Back Pain and Sciatica between Common treatment Group and Common treatment with Traction treatment. Methods : This study was carried out on 40 patients with Low Back Pain and Sciatica who were hospitalized in Dongshin Univ. Oriental Hospital from January, 2003 to May, 2004. Group A of 20 patients were taken both common treatment and Traction treatment. And Group B of 20 patients were only taken common treatment. And at discharge day, we checked and compared VAS(Visual Analogue Scale) and ODI(Oswestry disability index) out of these two groups. SPSS(Statistical Program for Social Science) for Window was used for a statistical analysis and the independent T-test was performed to gauge the improvement of VAS(Visual Analogue Scale) and ODI(Oswestry disability index) out of these two groups, in which case, value of P below 0.05 is considered as useful. Results : The result of the VAS(Visual Analogue Scale) and ODI(Oswestry disability index) of comparison analysis between two groups at discharge day, shows that the improvement of Low Back Pain and Sciatica in cmmon treatment with Traction treatment Group is more effective than that in Common treatment.

차동 구동형 모바일 로봇의 효율적인 운용을 위한 우선순위 기반의 원격제어 시스템

이동현,Lee, Dong-Hyun 대한임베디드공학회 2020 대한임베디드공학회논문지 Vol.15 No.2

In situations where mobile robots are operated either by autonomous systems or human operators, such as smart factories, priority-based teleoperation is crucial for the multiple operators with different priority to take over the right of the robot control without conflict. This paper proposes a priority-based teleoperation system for multiple operators to control the robots. This paper also introduces an efficient joystick-based robot control command generation algorithm for differential-drive mobile robots. The proposed system is implemented with ROS (Robot Operating System) and embedded control boards, and is applied to Pioneer 3AT mobile robot platform. The experimental results demonstrate the effectiveness of the proposed joystick control command algorithm and the priority-based control input selection.

뇌경색환자 치험 1례를 통한 오행침(五行鍼)과 육기침(六氣鍼)의 연구

이동현,정영표,정효근,이은방,류충열,조명래,채우석,나건호,Lee, Dong-Hyun,Jeong, Yeong-Pyo,Jeong, Hyo-Keun,Lee, Eun-Bang,Ryu, Chung-Ryul,Cho, Myung-Rae,Chae, Woo-Seok,Na, Gun-Ho 대한동의생리학회 2006 동의생리병리학회지 Vol.20 No.6

The purpose of this case is to report the improvement after treatment about a patient with cerebral infarction by Sa-Am's Ohaeng-acupuncture and Liuqi-acupuncture. We treated the patient with acupuncture therapy from 6th September 2004 to 15th November 2004 Dy reinforcing Dadun(LR 1)Zusan Li(5736) Quchi(Li 11) and reducing Taibai(Sp 3) on the basis of etiological analysis and differentiation of endogenous wind caused by damp phlegm and heat. Right hemiplegia improved Gr. 1 to Gr. tV after acupuncture therapy. We interpreted 'reinforcing Dadun(LR 1) and reducing TaiDai(SP 3)'as using Simjeonggyeok in conjunction with Simseunggyeok on the basis of Sa-Am's Ohaeng-acupuncture. We interpreted 'reinforcing Dadun(LR 1) and reducing Taibai(Sp 3)' as excreting dampness in Spleen on the basis of Liuqi-acupuncture. We interpreted 'reinforcing Zusan Li(57 36) and Quchi(Li 11)' as eliminating wind-dampness and menstrual regulation.

퇴비단 여과재 구성에 따른 혐기소화액 여과 효과

이동현,정광화,김중곤,곽정훈,안희권,김은종,Lee, Dong-Hyun,Jeong, Kwang-Hwa,Khan, Modabber Ahmed,Kim, Jung-Gon,Kwak, Jung-Hun,Ahn, Heekwon,Kim, Eun-Jong 한국축산환경학회 2013 한국축산시설환경학회지 Vol.19 No.1

This study was carried out to compare the filtration effect of anaerobic digestion waste water by compost filtration bed. Three types of filtration systems were set for filtration test following to composition of bedding materials. Two filtration systems were filled with sawdust, rice-hull and wood-chip. And the other was filled with sawdust and rice-hull. Anaerobic digestion waste water was applied evenly on the surface of the filtration bed with spraying nozzle. The concentration of nitrogen, biochemical oxygen demand (BOD), suspended solids (SS) of anaerobic digestion waste water was decreased by filtration treatment. The total nitrogen content was decreased from 1,313 mg/L to 1,090~1,293 mg/L and BOD concentration was decreased from 529.7 mg/L to 125~162.3 mg/L, respectively. The SS content was decreased from 69~79% by filtration process. In addition, the electrical conductivity (EC) was decreased from 10.22 ds/m to 7.91~8.31 ds/m.

PRMS: Page Reallocation Method for SSDs

이동현,노홍찬,박상현,Lee, Dong-Hyun,Roh, Hong-Chan,Park, Sang-Hyun Korea Information Processing Society 2010 정보처리학회논문지D Vol.17 No.6

Solid-State Disks (SSDs)는 빠른 접근 시간, 적은 전력소모, 전기 충격에의 내성과 같은 장점으로 인해 하드 디스크를 대체 할 것으로 기대되고 있다. 그러나 SSDs는 임의 쓰기(random write)로 인한 수명 단축이란 단점이 있으며 이는 SSDs 컨트롤러의 구조와는 별개로 나타나고 있다. SSDs와 관련한 기존 연구는 컨트롤러의 더 나은 디자인과 쓰기 연산의 감소에 주력하였다. 본 연구는 동시에 쓰여지는 경향이 있는 여러 데이터 페이지를 연속적인 블록에 배치하는 방법을 제시한다. 이 방식은 우선 특정 기한 동안 쓰기 연산에 대한 정보를 수집한 후 상기 쓰기 연산에 대한 정보를 트랜잭션화 하여 frequent itemset을 추출하고 이를 연속적인 블록에 재배치하는 과정으로 이루어진다. 또한 본 연구는 frequent itemset의 page를 재배치할 수 있는 알고리즘을 소개한다. TPC-C 기반 실험에 있어 본 연구가 제안한 재배치를 수행한 결과 저장 기기 접근 횟수를 평균 6 % 감소시킬 수 있었다. Solid-State Disks (SSDs) have been currently considered as a promising candidate to replace hard disks, due to their significantly short access time, low power consumption, and shock resistance. SSDs, however, have drawbacks such that their write throughput and life span are decreased by random-writes, nearly regardless of SSDs controller designs. Previous studies have mostly focused on better designs of SSDs controller and reducing the number of write operations to SSDs. We suggest another method that reallocates data pages that tend to be simultaneously written to contiguous blocks. Our method gathers write operations during a period of time and generates write traces. After transforming each trace to a set of transactions, our method mines frequent itemsets from the transactions and reallocates the pages of the frequent itemsets. In addition, we introduce an algorithm that reallocates the pages of the frequent itemsets with moderate time complexity. Experiments using TPC-C workload demonstrated that our method successfully reduce 6% of total logical block access.

요통(腰痛) 및 요각통(腰脚痛) 환자에 있어 약침치료(藥鍼治療)의 호전도에 대한 임상적 고찰

이동현,김효수,위통순,Lee, Dong-Hyun,Kim, Hyo-Soo,Wei, Tung-Shuen 대한약침학회 2004 Journal of pharmacopuncture Vol.7 No.2

Objectives : The purpose of this study is to compare the improvement rate in managering patients who had lumbago and pain in loin & feet by herbal-acupunture therapy with conservative treatment. Methods : 40patients who invited from March. 2003 to May. 2004 with lumbago and pain in loin & feet inve, were divided into two classes. A class was managed with conservative treatment(acupuncture, herb med, negative therapy, bed rest and physical therapy) and herbal-acupuncture therapy, the other class was managed with conservative treatment only. Two classes were distributed by sex and age, therapeutic periods, radiolographic results and therapeutic results that checked with VAS(visual analog scale) and ODI(Oswestry disability index). Results : According to VAS and OBI results, A class was managed with conservative treatment and herbal-acupuncture therapy shows the improvement in controling the pain of lumbago etc. comparing with the other class.