하반기 주요국 경기 판단 및 전망 - 디커플링되는 주요국 경기 속 커지는 중국 리스크

이형석,신지영,이부형,이형석,노시연,이부형 현대경제연구원 2023 현안과 과제 Vol.2023 No.12

DEA 모형을 이용한 한국 철강 산업의 효율성 분석

이형석,김기석 한국콘텐츠학회 2007 한국콘텐츠학회논문지 Vol.7 No.6

The steel industry plays an important role in the entire Korean Economy. However, little empirical research has analyzed the efficiency of steel companies. The purpose of this paper is to measure and analyze their efficiency using DEA models. We evaluate the CCR and BCC efficiency and the return to scale of 28 Korean steel companies. We also provide their envelopment map and the projection, which are valuable information for inefficient companies to find benchmarking companies and to improve their efficiency. 철강 산업은 자동차, 조선, 가전, 건설 등 전체산업에 기초소재를 공급하는 국가 기간산업으로서 ‘산업의 쌀’이라 할 만큼 중요한 산업이며, 철강업체들이 경쟁력을 강화하기 위해서는 정확한 효율성 분석이 필수적이다. 본 논문에서는 DEA 모형을 이용하여 한국 철강업체들의 효율성을 분석하였다. DEA 모형 중에서 CCR 모형과 BCC 모형을 사용하였으며, 분석에 선정된 28개 철강업체들의 2005년도 효율성(CCR, BCC, 규모)과 규모수익성(RTS)을 분석하였다. 또한 분석된 자료를 바탕으로 벤치마킹의 대상을 찾기 위한 포락지도(envelopment map)와 이에 따라 효율적이 되기 위한 목표 값을 제시하였으며, 산업분류를 세분류와 세세분류로 나누어서 각 산업별로 효율성을 파악하였다.

일측성 광대뼈골절 환자에서 수평계와 자를 이용한 변위 교정의 간단한 파악법

이형석,이경석,김준식,김남균,Yi, Hyung-Suk,Lee, Kyung-Suk,Kim, Jun-Sik,Kim, Nam-Gyun 대한성형외과학회 2010 Archives of Plastic Surgery Vol.37 No.2

Purpose: The zygoma is a key element which composes the facial contour. Zygomatic fracture induces facial asymmetry. We use radiologic evaluation or inspections mainly for identification of symmetry after reduction depressed zygomatic fracture. But the disadvantages of such methods are time-consuming and complicated process. So we tried to develop a new testing method with a ruler and a level. Methods: In unilateral depressed zygomatic fracture patient, parallel to the patient's head to make sure lay horizontaly. Put the leg of a ruler on the malar eminence so that it is at the same distance from the facial midline. Then take the level of malar eminence as put the level above the ruler. This process was performed before and after the reduction. Results: We were able to fix with plate and screw after checking the results of reduction fast and easily. Good results were obtained at post-operative radiologic evaluation. Conclusion: We can easily get the ruler and level around life. This method is not only simple but also shorttime process compared with other method-radiologic evaluation or inspection. And the operator can explain the results to the patients easily and objectively. Authors obtained the good results with this new method, and would introduce it for another method of identifying the result of reduction in depressed zygomatic fractures.

유잉육종과 관련된 말초성 안면신경마비

이형석,신동익,문소영,한호성,이성현,이상수,한현정,오화은 대한신경과학회 2008 대한신경과학회지 Vol.26 No.4

밸런스패드를 이용한 스쿼트 훈련이 뇌졸중 환자의 균형 및 보행에 미치는 영향

이형석,양대중 대한고유수용성신경근촉진법학회 2025 PNF and Movement Vol.23 No.1

Purpose: This study aimed to investigate the effects of squat exercises on balance and gait in stroke patients using a balancepad. Methods: Thirty stroke patients were divided into two groups: the squat exercise with balance pad group (n = 15) and the generalphysical therapy group (n = 15). The sample size was calculated using the G*Power 3.1.9.7 program. Balance was assessed usingthe Physiosensing platform by measuring the weight distribution ratio, sway area, and limits of stability. Gait was assessed usingthe G-Walk system by measuring cadence, walking speed, and step length. Within-group comparisons were performed usingpaired t-tests and between-group comparisons were conducted using ANCOVA, with pre-intervention values set as covariates. The intervention was conducted 5 times per week for 8 weeks. Results: A within-group analysis revealed significant improvements in all variables in the experimental group, which performedsquat exercises using the balance pad. In the control group, which received general physical therapy, significant improvementswere observed in the weight distribution ratio, limits of stability, cadence, and walking speed. The between-group analysisdemonstrated significantly greater improvements in all variables in the experimental group than in the control group. Conclusion: The findings of this study indicate that squat exercises using a balance pad are effective in improvingbalance and gait abilities in stroke patients.

광위상 간섭을 이용한 이송축의 운동오차 실시간 보상

이형석,김승우 대한기계학회 1993 대한기계학회논문집 Vol.17 No.12

This paper presents a real-time correction method of the movemont errors of a translatory precision machine axis. This method is a null-balances technique in which two plane mirrors are used to generate an interferometric fringe pattern utilizing the optical principles of TwymanGreen interferometry. One mirror is fixed on a reference frame, while the other is placed on the machine axis being supported by three piezoelectric actuators. From the fringe pattern, one translatory and two rotational error components of the machine axis are simultaneously detected by using CCD camera vision and image processing techniques. These errors are then independently suppressed by activating the peizoelectric actuators by real-time feedback control while the machine axis is moving. Experimental results demonstrate that a machine axis can be controlled with movement errors less than 10 nm in vertical straightness, 0.1 arcsec in pitch, and 0.06 arcsec in roll for 50mm travel by adopting the real-time correction method.

Hydro-elastic analysis of marine propellers based on a BEM-FEM coupled FSI algorithm

이형석,송민철,서정천,장봉준 대한조선학회 2014 International Journal of Naval Architecture and Oc Vol.6 No.3

A reliable steady/transient hydro-elastic analysis is developed for flexible (composite) marine propeller blade design which deforms according to its environmental load (ship speed, revolution speed, wake distribution, etc.) Hydro-elastic analysis based on CFD and FEM has been widely used in the engineering field because of its accurate results however it takes large computation time to apply early propeller design stage. Therefore the analysis based on a boundary element method-Finite Element Method (BEM-FEM) Fluid-Structure Interaction (FSI) is introduced for com-putational efficiency and accuracy. The steady FSI analysis, and its application to reverse engineering, is designed for use regarding optimum geometry and ply stack design. A time domain two-way coupled transient FSI analysis is dev-eloped by considering the hydrodynamic damping ffects of added mass due to fluid around the propeller blade. The analysis makes possible to evaluate blade strength and also enable to do risk assessment by estimating the change in performance and the deformation depending on blade position in the ship’s wake. To validate this hydro-elastic analysis methodology, published model test results of P5479 and P5475 are applied to verify the steady and the transient FSI analysis, respectively. As the results, the proposed steady and unsteady analysis methodology gives sufficient accuracy to apply flexible marine propeller design.

대형할인점의 쿠폰상환의도에 영향을 미치는 요인연구

이형석,여민선,최은교 한국경영과학회 2009 한국경영과학회 학술대회논문집 Vol.2009 No.10

당뇨병 환자에서 상완동맥-두정맥 동정맥루조성술 후에 발생한 허혈성 단일사지신경병증

이형석,서민정,이현동 대한혈관외과학회 2013 Vascular Specialist International Vol.29 No.2

Ischemic monomelic neuropathy (IMN) is recognized as a rare ischemic neuropathy caused by vascular access originating from the brachial artery leading to hemodialysis. IMN is characterized by acute painful muscle weakness shortly after surgery and neuronal axon loss without necrosis of adjacent tissues. In chronic diabetic patients with polyneuropathy, brachial vascular access surgeries include the risk of IMN, necessitating immediate surgical treatment such as banding or ligation. In the above case, we chose to close brachial-cephalic arteriovenous fistula for IMN with no short-term neurologic improvement, however, significant neurological and clinical improvement was observed in long-term follow-up. Here, we present a case of IMN with serial nerve conduction evaluations indicating the improved long-terms outcomes.

봄철 크리핑 벤트그래스의 품종별 특성비교

이형석,홍범석,김경덕,태현숙 한국잔디학회 2007 Weed & Turfgrass Science Vol.21 No.2

This study was initiated to evaluate the growth characteristics of creeping bentgrass cultivars during the spring season. The green-up of ‘CY’ and ‘T-1’ were about 2 weeks earlier than the other cultivars followed by ‘Penn A’‘Crenshaw’, 'L> ‘Penncross’ > ‘Putter’ > ‘Dominant’ > ‘SR1020’ in that order. ‘T-1’ and ‘CY-2’ had the highest chlorophyll content while ‘Penncross’ had the lowest during the spring. ‘Crenshaw’ and ‘Penn A-4’ showed the highest shoot density in this research, followed by 'CY-2', ‘L-93’, ‘T-1’, ‘Putter’, ‘Dominant’, ‘SR1020’, and ‘Penncross’ in that order. In case of root length, ‘CY-2’ and ‘L-93’ were the best cultivars, but ‘Penncross’ was worst during the spring. ‘CY-2’ had the best visual quality among the cultivars, ‘T-1’ and ‘Crenshaw’ also classified as high visual quality group whereas ‘SR1020’, ‘Dominant’ and ‘Penncross’ were grouped in relatively low quality. In conclusion, ‘CY-2’, ‘T-1’ and ‘Crenshaw’ were the best cultivars in terms of growth characteristics in spring. Conversely, ‘SR1020’ and ‘Penncross’ were the poorest cultivars. These results can be more useful for management or constructing of golf courses. However, this research was performed with little compaction stress. More information is needed on the tolerance to compaction stress of these bentgrass cultivars. 본 연구는 봄철 크리핑 벤트그래스의 품종별 생육특성을 파악하고자 수행하였다 . 먼저 그린업 조사결과 , CY-2와 T-1의 초기 그린업이 가장 빨랐으며 이는 다른 품종들보다 2주 정도 빨리 진행된 것으로 나타나 봄철 그린업 속도에 따른 품종별 별도의 관리 프로그봄철 크리핑 벤트그래스의 품종별 특성비교 161램이 필요할 것으로 생각 되었다 . 나머지 품종들의 그린업은 Penn A­4, Crenshaw, L­93 > Pencross > Puter > Dominant > SR1020순으로 조사되었다. 클로로필 함량은 T-1과 CY-2가 가장 높았고, Pencros 는 현저히 낮은 수치를 보였다 . 잔디 밀도가 가장 높았던 품종은 Crenshaw, Pen A-4 이고, 다음으로 CY-2, L-93, T-1, Puter, Dominant, SR1020, Penncross 순으로 높게 나타났다 . 봄철 뿌리생육이 가장 우수한 품종은 CY-2와 L-93이었고, 가장 불량한 품종은 Pencros 였다. 시각적 품질은 CY-2가 가장 좋았으며 , T-1과 Crenshaw 도 우수한 품종으로 분류되었다. SR1020, Dominant 및 Pencros 의 시각적 품질은 낮았으나 잔디생육이 활발한 6월에 접어들면서 품종별 차이는 없어졌다.본 실험의 결과를 종합해 보면 봄철 생육이 가장 우수한 품종은 CY-2, T-1, Crenshaw이었으며, 가장 불량하였던 품종은 SR1020, Pencros 였다. 조사된 다양한 결과들은 많은 골프장 그린의 품종 선택과 초기 관리에 유용한 정보가 될 것으로 생각된다 . 앞으로 잔디병과 답압 스트레스를 포함한 다양한 항목에 대한 조사가 수행되어야 할 것이다 .