대용변수를 이용한 $\bar{X}$ 관리도의 경제적 설계

이태훈,이재훈,이민구,이주호,Lee, Tae-Hoon,Lee, Jae-Hoon,Lee, Min-Koo,Lee, Joo-Ho 한국품질경영학회 2009 품질경영학회지 Vol.37 No.2

The traditional approach to economic design of control charts is based on the assumption that a process is monitored using a performance variable. However, various types of automatic test equipments recently introduced as a part of factory automation usually measure surrogate variables instead of performance variables that are costly to measure. In this article we propose a model for economic design of a control chart which uses a surrogate variable that is highly correlated with the performance variable. The optimum values of the design parameters are determined by maximizing the total average income per cycle time. Numerical studies are performed to compare the proposed $\bar{X}$ control charts with the traditional model using the examples in Panagos et al. (1985).

변형 Weil 절골술의 중족지 단축 효과를 이용한 Freiberg병의 치료

이태훈,이영현,안길영,남일현,이경진,우상원,Lee, Tae-Hoon,Lee, Yeong-Hyeon,Ahn, Gil-Yeong,Nam, Il-Hyun,Lee, Kyung-Jin,Woo, Sang-Won 대한족부족관절학회 2021 대한족부족관절학회지 Vol.25 No.4

Purpose: This study sought to evaluate the clinical effectiveness of the shortening effect of the modified Weil osteotomy for the treatment of Freiberg's disease. Materials and Methods: We reviewed 21 cases treated with the modified Weil osteotomy for Freiberg's disease from November 2005 to June 2019. The average follow-up period was 32.5 months and the mean age of the patients was 38.3 years. The clinical results were analyzed using the American Orthopaedic Foot and Ankle Society (AOFAS) lesser metatarsophalangeal-interphalangeal scale, the visual analogue scale (VAS), and the range of motion (ROM) of the metatarsophalangeal joint. In the radiologic evaluation, the length of preoperative and postoperative metatarsal shortening was compared. Results: The average AOFAS lesser metatarsophalangeal-interphalangeal scale showed an improvement from 60.5 preoperatively to 90.9 at the latest follow-up. VAS showed a decrease from 5.4 preoperatively to 0.9 at the latest follow-up. ROM of the affected metatarsophalangeal joint increased from 40.2 degrees preoperatively to 58.6 degrees at the latest follow-up. The mean length of metatarsal shortening was 6.7 mm. There was no transfer metatarsalgia, osteonecrosis, and definite joint space narrowing. Conclusion: Modified Weil osteotomy with second layer cutting is an effective treatment option to restore the joint surface and painless joint motion for patients with Freiberg's disease.

대용변수를 이용한 가변형 부분군 크기 ${\bar{X}}$ 관리도의 경제적 설계

이태훈,이민구,권혁무,홍성훈,이주호,Lee, Tae Hoon,Lee, Min Koo,Kwon, Hyuck Moo,Hong, Sung Hoon,Lee, Jooho 한국품질경영학회 2017 품질경영학회지 Vol.45 No.4

Purpose: This paper proposes a VSS(Variable Sample Size) ${\bar{X}}$ control chart using surrogate variable and shows its effectiveness compared with FSS(Fixed Sample Size) ${\bar{X}}$ control chart using either performance variable or surrogate variable. Methods: The expected cost function of VSS ${\bar{X}}$ control chart is derived. The optimal designs are then found for numerical examples using a GA(genetic algorithm) and compared to those of the FSS ${\bar{X}}$ control charts. Results: Computational results show that VSS ${\bar{X}}$ control chart using surrogate variables is superior to FSS ${\bar{X}}$ control chart using either performance variable or surrogate variable from the economic view points. Conclusion: The proposed VSS ${\bar{X}}$ control chart will be useful in industry fields where a performance variable is not avaliable or too costly.

부주상골을 동반한 이분 내측 설상골: 증례 보고

이태훈,남일현,문기혁,이영현,안길영,이영훈,Lee, Tae-Hoon,Nam, Il-Hyun,Moon, Gi-Hyuk,Lee, Yeong-Hyeon,Ahn, Gil-Yeong,Lee, Young-Hoon 대한족부족관절학회 2015 대한족부족관절학회지 Vol.19 No.1

Accessory navicular is a congenital anomaly appearing in the secondary ossification center on the tuberosity of the navicular that may cause flatfoot. Bipartite medial cuneiform is another rare congenital anomaly occurring as two primary ossification centers in the medial cuneiform. The authors report a rare case of symptomatic bilateral accessory navicular with bipartite medial cuneiform and flatfoot deformity in a 19-year-old man with a review of the literature.

임베디드 시스템을 위한 신뢰성 있는 NAND 플래시 파일 시스템의 설계

이태훈,박송화,김태훈,이상기,이주경,정기동,Lee Tae-hoon,Park Song-hwa,Kim Tae-hoon,Lee Sang-gi,Lee Joo-Kyong,Chung Ki-Dong 한국정보처리학회 2005 정보처리학회논문지 A Vol.12 No.7

NAND 플래시 메모리는 저전력 소비, 비휘발성, 읽기 속도의 항상 등의 장점이 있다. 그러나 제자리 덮어쓰기(in-place-update)가 불가능하고 지우는 횟수에 제한이 있으며 페이지 단위로 연산이 수행되는 단점이 있다. 이러한 NAND 플래시 메모리를 위한 전용 파일 시스템으로 YAFFS가 개발되었지만 여러 가지 문제점이 존재한다. 본 논문에서는 빠른 복구를 위한 기법, 효율적인 데이터 갱신 기법 그리고 균등한 메모리 사용을 위한 플레인 지움 정책을 사용하는 파일 시스템을 제안한다 전원 오류 발생시, 로그 정보를 사용하여 빠른 복구를 지원한다. 그리고 플래시 메모리의 효율적인 사용을 위해 데이터 쓰기 양을 최소화하고 이를 위해 새로운 메타 데이터 구조를 제안한다. 또한 플레인 지움 정책은 플래시의 균등 사용과 임베디드 시스템의 제한된 자원을 고려하여 연산을 최소화한다. 제안된 기법들의 성능을 실험을 통해 증명하고 그 결과를 분석한다. NAND flash memory has advantages of non-volatility, little power consumption and fast access time. However, it suffers from inability that dose not provide to update-in-place and the erase cycle is limited. Moreover, the unit of read and write operations is a page. A NAND flash file system called YAFFS has been proposed. But YAFFS has several problems to be addressed. In this paper, the Reliable Flash File System(RFFS) for NAND flash memory is designed and evaluated. In designing a file system the following four issues must be considered in particular for the design: (i) to minimize a repairing time when the system fault occurs, (ii) to balance the number of block erase operations by offering wear leveling policy, and (iii) to reduce turnaround time of memory operations by reducing the amount of data written. We demonstrate and evaluate the performance of the proposed schemes.

강화도 석모도 지역에서의 효율적인 조력발전방식 비교

이태훈,심주열,조용식,Lee,Tae-Hoon,Sim,Ju-Yeol,Cho,Yong-Sik 한국방재학회 2008 한국방재학회 학술발표대회논문집 Vol.2008 No.1

The huge economical damage and environmental pollution have been occurred for decades because of using of fossil fuel. So the development of alternative energy is urgent. In the west sea of Korea, a proper area for tidal power plant, development and investigation for economical efficient of tidal power plant are preceeding. The water turbine generator with the capacity of 25.4MW was used to compare single-basin flood tide generation with ebb tide generation while considering the water depth and tide in the vicinity of Sukmodo.

편평족의 진단

이태훈,최서우,김학준,Lee, Tae Hoon,Chay, Suh Woo,Kim, Hak Jun 대한족부족관절학회 2016 대한족부족관절학회지 Vol.20 No.1

Flatfoot is defined as loss of medial arch with hindfoot valgus, but normal condition is obscure due to wide individual variance. Loss or decreasing of medial longitudinal arch with radiographic image is clinically diagnosed as flatfoot. Flatfoot without symptoms is not an indication for treatment. The etiologies of flatfoot are congenital cause, hypermobility, tarsal coalition, neuromuscular disease, post-traumatic deformity, Charcot arthropathy, and posterior tibial tendon dysfuction. The flatfoot is classified as congenital and acquired, flexible, and rigid. The diagnosis is made by physical examination and radiographic findings. In particular, the posterior tibial tendon dysfunction is known as adult acquired flatfoot.

급성 아킬레스건 파열의 치료

이태훈,김학준,전영식,Lee, Tae Hoon,Kim, Hak Jun,Jeon, Young Sik 대한족부족관절학회 2015 대한족부족관절학회지 Vol.1 No.2

Acute Achilles tendon rupture is a frequent injury during sports and recreational activities. Treatments for Achilles tendon rupture have been controversial in recent decades. Traditionally the surgical treatment had benefit over nonsurgical treatment in terms of low rerupture rate and early functional restoration. Recently, nonsurgical treatment was found to show no statistically significant inferiority in re-rupture rate, functional outcome, and calf strength. Whereas, surgical treatment had some complications including adhesion, nerve injury, and infection. Nonsurgical treatment has been increasing due to functional rehabilitation with early weight bearing and restricted early motion. It focuses more attention on the course of caring for patients with deep discussion. There are open repair and minimally invasive repair in terms of surgical treatment. There are various techniques for minimally invasive repair of Achilles tendon, which has some advantages over the open repair. However, the optimal technique for minimally invasive repair has not been established. The number of suture strands is important regardless of suture technique.

Er³⁺ 첨가 유리의 1.55μm 형광특성에 미치는 Thermal Poling의 영향

이태훈,정운진,허종,Lee, Tae-Hoon,Chung, Woon-Jin,Heo, Jong 한국세라믹학회 2003 한국세라믹학회지 Vol.40 No.5

1.55$\mu$m 파장대 광증폭용 재료의 이득 파장대역 증대를 목적으로 Er$^{3+}$ 첨가 유리에 대해 thermal poling이 형광스펙트럼 의 반가폭(full width at half maximum)에 미치는 영향을 분석하였다. 텔루라이트 유리(TeO$_2$-ZnO)의 경우 poling후 약 6%의 형광 반가폭 증가가 관찰된 반면 다른 유리에서는 감소하거나 변화가 없었다. 이와 같은 형광스펙트럼의 변화는 알려진 바와 같이 poling으로 인해 유리내에 생성된 전하 결핍층과 이러한 결핍층에 발생하는 잔류 정전기장 때문으로 판단된다. 실리케이트 등과 같은 다른 유리와는 달리 텔루라이트 유리에서만 Er$^{3+}$ 의 형광 반가폭이 증가한 것은 유리를 구성하고 있는 TeO$_4$에 존재하는 비공유 전자쌍과 밀접하게 관련되어 있을 것으로 추측된다. Effect of the thermal poling on the 1.55 fm emission spectra in various Er$^{3+}$ -doped glasses was investigated with a special attention on the changes in the values of FWHM(Full Width at Half Maximum) intensity. Tellurite glasses poled at 28$0^{\circ}C$ with an electric voltage of 4 kV resulted in an approximately 6% increase in FWHM values compared with their unpoled counterparts. On the other hand, values for glasses, such as aluminosilicate, sulfide and chalcohalide, either decreased or remained unchanged. The characteristic results from tellurite glasses are most probably due to the presence of lone-pair electrons in the TeO$_4$ hi-pyramidal units that form the main network structure of tellurite glasses.

모델 체킹에서 안전성 위반에 대한 효율적인 반례 생성

이태훈,권기현,Lee Tae-hoon,Kwon Gi-hwon 한국정보처리학회 2005 정보처리학회논문지D Vol.12 No.1

모델 체킹은 주어진 모델과 속성간의 만족성 관계를 검사한다. 만일 모델이 속성을 만족하지 않는 경우, 모델 체킹은 그 이유를 담은 반례를 생성한다. 반례는 모델의 디버깅에 사용되며 모델을 이해하는데 도움을 주기 때문에, 반례 생성은 모델 체킹의 필수 구성 요소 중의 하나이다. 본 논문에서는 모델 체킹에서 안전성 속성이 위반되었을 때 그에 대한 반례를 효율적으로 생성하는 방법을 제시하였고, 푸쉬 푸쉬 게임 풀이에 제안한 방법을 적용했다. 그 결과, 기존 NuSMV로는 전체 50게임 중에서 42게임밖에 풀지 못했으나 본 논문의 방법으로는 50게임을 모두 풀었다. 뿐만 아니라, 반례 생성에 소요된 시간과 메모리 사용량이 기존 NuSMV에 비해서 각각 $86{\%}$와 $62{\%}$ 개선되었다. Given a model and a property, model checking determines whether the model satisfies the property. In case the model does not satisfy the property model checking gives a counterexample which explains where the violation occurs. Since counterexamples are useful for model debugging as well as model understanding, counterexample generation is one of the indispensable components in the model checking tool. This paper presents efficient counterexample generation techniques when a safety property is falsified. These techniques are used to solve Push Push games which consist of 50 games. As a result, all the games are solved with the proposed techniques. However, with the original NuSMV, 42 games are solved but 8 failed. In addition, we obtain $86{\%}$ time improvement and $62{\%}$ space improvement compared to the original NuSMV in solving the game.