• Asian Pacific Journal of Cancer Prevention
• /
• 제15권13호
• /
• pp.5395-5399
• /
• 2014

Purpose: This study was designed to evaluate the outcomes of laparoscopic colorectal resection in a period of learning curve completed by surgeons with different experience and aptitudes with a view to making clear whether seniors had a better learning curve compared with juniors. Methods: From May 2010 to August 2012, the first twenty patients underwent laparoscopic colorectal resection completed by each surgeon were selected for analysis retrospectively. A total of 240 patients treated by 5 seniors and 7 juniors were divided into the senior group (n=100) and the junior group (n=140). The short-term outcomes of laparoscopic surgery of the two groups were compared. Results: The mean numbers of lymph nodes harvested were $21.2{\pm}11.0$ in the senior group and $17.3{\pm}11.5$ in the junior group (p=0.010); The mean operative times were $187.9{\pm}60.0min$ as compared to $231.3{\pm}55.7min$ (p=0.006), and blood loss values were $177.0{\pm}100.7ml$ and $234.0{\pm}185ml$, respectively (p=0.001); Conversion rate in the senior group was obviously lower than in the junior group (10.0% vs 20.7%, p=0.027) and the mean time to passing of first flatus were $3.3{\pm}0.9$ and $3.8{\pm}0.9$ days (p=0.001). For low rectal cancer, the sphincter preserving rates were 68.7% and 35.3% (p=0.027). Conclusions: Seniors could perform laparoscopic colorectal resection with relatively better oncological outcomes and quicker recovery, and seniors could master the laparoscopic skill more easily and quickly. Seniors had a better learning curve for laparoscopic colorectal cancer resection compared to juniors.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2005년도 학술발표회 논문집
• /
• pp.679-683
• /
• 2005

The technique which connects Generalized Regression Neural Networks Model(GRNNM) with Genetic Algorithm (CA) is used to derive rating curve in the river basin. GRNNM architecture consists of 4 layers ; input, hidden, summation and output layer. GA method is applied to estimate the optimal smoothing factor when GRNNM is trained. The derivation of rating curve using GRNNM is considered different kinds of hydraulic characteristics such as water stage, area and mean velocity and is applied two stage stations; Sunsan and Jungam. Furthermore, it is compared with conventional curve-fitting method. Through the training and validation performance, the results show that GRNNM is much superior as compared to the conventional curve-fitting method.

• 호남수학학술지
• /
• 제46권1호
• /
• pp.12-37
• /
• 2024

The paper introduces a set of new ruled surfaces such that the base curve is taken to be the striction curve of N, C and W ruled surfaces from the alternative frame, and the generating line is taken to be one of the vectors of Sannia frame. The characterizations for each ruled surface such as fundamental forms, the Gaussian and mean curvature are also examined to provide the conditions for each surface to be developable or minimal.

• Nuclear Engineering and Technology
• /
• 제38권3호
• /
• pp.277-284
• /
• 2006

In order to ensure the structural integrity of nuclear welded structures during design life, the fatigue life has to be evaluated by fatigue analysis procedures presented in technical codes such as ASME B&PV Code Section III. However, existing fatigue analysis procedures do not explicitly consider the presence of welded joints. A new fatigue analysis procedure based on a structural stress/fracture mechanics approach has been recently developed in order to reduce conservatism by erasing uncertainty in the analysis procedure. A recent review of fatigue crack growth data under various mean loading conditions using the structural stress/fracture mechanics approach, does not consider the mean loading effect, revealed some significant discrepancies in fatigue crack growth curves according to the mean loading conditions. In this paper, we propose the use of the stress intensity factor range ${\Delta}K$ characterized with loading ratio R effects in terms of the structural stress. We demonstrate the effectiveness in characterizing fatigue crack growth and S-N behavior using the well-known data. It was identified that the S-N data under high mean loading could be consolidated in a master S-N curve for welded joints.

• 대한수학회보
• /
• 제61권2호
• /
• pp.401-419
• /
• 2024

Let K, H, K_II and H_II be the Gaussian curvature, the mean curvature, the second Gaussian curvature and the second mean curvature of a timelike tubular surface T_γ(α) with the radius γ along a timelike curve α(s) in Minkowski 3-space E³₁. We prove that T_γ(α) must be a (K, H)-Weingarten surface and a (K, H)-linear Weingarten surface. We also show that T_γ(α) is (X, Y)-Weingarten type if and only if its central curve is a circle or a helix, where (X, Y) ∈ {(K, K_II), (K, H_II), (H, K_II), (H, H_II), (K_II , H_II)}. Furthermore, we prove that there exist no timelike tubular surfaces of (X, Y)-linear Weingarten type, (X, Y, Z)-linear Weingarten type and (K, H, K_II, H_II)-linear Weingarten type along a timelike curve in E³₁, where (X, Y, Z) ∈ {(K, H, K_II), (K, H, H_II), (K, K_II, H_II), (H, K_II, H_II)}.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2011년도 춘계학술대회 논문집
• /
• pp.1557-1558
• /
• 2011

• 한국농공학회논문집
• /
• 제60권6호
• /
• pp.97-109
• /
• 2018

The LDC (Load Duration Curve) method can analyze river water quality changes according to flow rate and seasonal conditions. It is also possible to visually recognize whether the target water quality is exceeded or the size of the reduction load. For this reason, it is used for the optimal reduction of TPLCs and analysis of the cause of water pollution. At this time, the flow duration curve should be representative of the water body hydrologic curve, but if not, the uncertainty of the interpretation becomes big because the damaged flow condition is changed. The purpose of this study is to estimate the daily mean flow of the unit watershed using the HSPF model and to analyze the difference of the flow duration curves according to the cumulative daily mean flow rate using the NSE technique. The results show that it is desirable to construct the flow duration curve by using the daily average flow rate of at least 5 years although there is a difference by unit watershed. However, this is the result of the water bodies at the end of Han River basin watershed, so further study on various water bodies will be necessary in the future.

• 대한기계학회논문집A
• /
• 제33권9호
• /
• pp.930-937
• /
• 2009

The estimation method of the fracture resistance curve for the pipe specimen was proposed using the load ratio method for the standard specimen. For this, the calculation method of the load - CMOD curve for the pipe specimen with the common format equation(CFE) was proposed by using data of the CT specimen. The proposed method agreed well with experimental data. The J-integral value and the crack extension were calculated from the estimated load - CMOD data. The fracture resistance curve was estimated from the calculated J-integral and the crack extension. From these results, it have been seen that the proposed method is reliable to estimate the J-R curve of the pipe specimen.

• 한국수학교육학회지시리즈B:순수및응용수학
• /
• 제27권2호
• /
• pp.83-96
• /
• 2020

In this paper we study Biharmonic curves, Legendre curves and Magnetic curves in three dimensional f-Kenmotsu manifolds. We also study 1-type curves in a three dimensional f-Kenmotsu manifold by using the mean curvature vector field of the curve. As a consequence we obtain for a biharmonic helix in a three dimensional f-Kenmotsu manifold with the curvature κ and the torsion τ, κ² + τ² = -(f² + f'). Also we prove that if a 1-type non-geodesic biharmonic curve γ is helix, then λ = -(f² + f').

• 품질경영학회지
• /
• 제30권4호
• /
• pp.106-119
• /
• 2002

The fatigue curve with estimated parameters represents the estimate of the median or mean life at a given applied stress But, in order to assist a designer in making decisions regarding the fatigue failure mode, it is common practice to construct a design curve on the lower or safe side of data. In this study, to overcome the limitations(i.e., no runout, equal variance, and quality of the approximation, etc) of Shen, Wirsching, and Cashman's method which suggested the approximate design curve for nonlinear models using tolerance interval constructed by Owen's method, an algorithm to find design curves under the fatigue model using a parametric bootstrap method, is proposed and illustrated with multiple fatigue data sets.