• Geomechanics and Engineering
• /
• v.21 no.6
• /
• pp.513-525
• /
• 2020

Slopes stabilised with piles are seldom analysed considering uncertainties in the parameters of the pile-slope system. Reliability analysis of the pile-slope system quantifies the degree of uncertainties and evaluates the safety of the system. In the present study, the reliability analysis of a slope stabilised with piles is performed using the first-order reliability method (FORM) based on Hasofer-Lind approach. The implicit performance function associated with the factor of safety (FS) of the slope is approximated using the response surface method. The analyses are carried out considering the design matrices formulated based on both the 2^k factorial design augmented with a centre run (2^k fact-centred design) and face-centered cube design (FCD). The finite element method is used as the deterministic model to compute the FS of the pile-slope system. Results are compared with the results of the Monte Carlo simulation. It is observed that the optimum location of the row of piles is at the middle of the slope to achieve the maximum FS. The results show that the reliability of the system is not uniform for different pile configurations, even if the system deterministically satisfies the target factor of safety (FS_t) criterion. The FS_t should be selected judiciously as it is observed that the reliability of the system changes drastically with the FS_t level. The results of the 2^k fact-centred design and FCD are in good agreement with each other. The procedure of the FCD is computationally costly and hence the use of 2^k fact-centred design is recommended, provided the response of the system is sufficiently linear over the factorial space.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.10 no.2
• /
• pp.134-142
• /
• 2010

A comparative study on the trade-off between the drive current and the total gate capacitance in double-gate (DG) and triple-gate (TG) FinFETs is performed by using 3-D device simulation. As the first result, we found that the optimum ratio of the hardmask oxide thickness ($T_{mask}$) to the sidewall oxide thickness ($T_{ox}$) is $T_{mask}/T_{ox}$=10/2 nm for the minimum logic delay ($\tau$) while $T_{mask}/T_{ox}$=5/1~2 nm for the maximum intrinsic gate capacitance coupling ratio (ICR) with the fixed channel length ($L_G$) and the fin width ($W_{fin}$) under the short channel effect criterion. It means that the TG FinFET is not under the optimal condition in terms of the circuit performance. Second, under optimized $T_{mask}/T_{ox}$, the propagation delay ($\tau$) decreases with the increasing fin height $H_{fin}$. It means that the FinFET-based logic circuit operation goes into the drive current-dominant regime rather than the input gate load capacitance-dominant regime as $H_{fin}$ increases. In the end, the sensitivity of $\Delta\tau/{\Delta}H_{fin}$ or ${{\Delta}I_{ON}}'/{\Delta}H_{fin}$ decreases as $L_G/W_{fin}$ is scaled-down. However, $W_{fin}$ should be carefully designed especially in circuits that are strongly influenced by the self-capacitance or a physical layout because the scaling of $W_{fin}$ is followed by the increase of the self-capacitance portion in the total load capacitance.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.44 no.10
• /
• pp.67-74
• /
• 2007

Turbo code, a kind of channel coding technique, has ben used in the field of digital mobile communication system if the number of iterations is increased in the several channel environments, my further iteration results in very little improvement, and requires much delay and computation in proportion to the number of iterations. In this paper, it proposes an efficient stopping rules for the iteration process in turbo decoding. By using absolute mean values for the LLR difference values between the first and second decoder in the present decoding process, the proposed algorithm can largely reduce the average number of iterations without BER performance degradation in all SNR regions. As a result of simulation, the average number of iterations of proposed algorithm is reduced by about $18.25%{\sim}20.58%$ compared to SDR algerian in the lower SNR region, and is reduced by about $22.96%{\sim}28.74%$ compared to method using variance values of extrinsic information in the upper SNR region.

• Proceedings of the Acoustical Society of Korea Conference
• /
• spring
• /
• pp.95-98
• /
• 2002

문자인식 또는 음성인식을 위해 사용되어지는 CHMM(Continuous Hidden Markov Model)모델은 일반적으로 모델의 상태수를 일정한 수로 고정하는 고정 상태수 모델 구조를 가지고 있으나, 이는 개별적인 인식 단위의 특성을 고려하지 않은 경우로써 이를 고려한 가변 상태수 모델을 사용할 경우 인식률 향상을 기대할 수 있다. 개별적인 인식 단위에 적합한 모델 상태수를 결정하는 방법으로 파라미터 히스토그램 방법과, BIC(Bayesian Information Criterion)방법을 사용하는 것이 대표적이다. 이들 방법들은 개별적인 인식단위의 우도값만을 향상시키기 위한 방법으로 전체인식률과 직접적으로 비례하지는 않는다. 따라서, 본 논문에서는 고정 상태수를 갖는 모델 적용 방법과 인식단위별 상태수 변화에 따른 인식률을 비교하였으며, 이를 바탕으로 각 모델별 상태수를 달리하는 가변 상태수 CHMM모델 구성 방법을 제안한다. 제안된 가변상태수 모델의 유효성을 확인하기 위해 음성/문자 공용인식기 중 필기체 문자 인식에 적용한 결과 제안한 LM(Local Maximum)으로 구성된 가변 상태수 모델이 MLE와 BIC로 구성된 모델과 인식률 면에서는 거의 동일한 성능을 유지하면서 전체 상태수는 MLE 모델에 비해 $31\%$, BIC로 구성된 모델에 비해 $22\%$ 감소를 나타내어 제안한 모델의 유효성을 확인할 수 있었다.

• Journal of the Korea Safety Management & Science
• /
• v.20 no.1
• /
• pp.41-55
• /
• 2018

For several decades, attribute classification methods using the asymmetrical relationship between an attribute performance and the satisfaction of that attribute have been explored by numerous researchers. In particular, the Kano model, which classifies quality attributes into 5 elements using simple questionnaire and two-dimensional evaluation table, has gained popularity: Attractive, One-dimensional, Must-be, Indifferent, and Reverse quality. As Kano's model is well accepted, many literatures have introduced categorization methods using the Kano's evaluation table at attribute level. However, they applied different terminologies and classification criteria and this causes confusion and misunderstanding. Therefore, a criterion for quality classification at attribute level is necessary. This study is aimed to suggest a new attribute classification method that sub-categorizes quality attributes using 5-point ordinal point and Kano's two-dimensional evaluation table through an extensive literature review. For this, the current study examines the intrinsic and extrinsic problems of the well-recognized Kano model that have been used for measuring customer satisfaction of products and services. For empirical study, the author conducted a comparative study between the results of Kano's model and the proposed method for an e-learning case (33 attributes). Results show that the proposed method is better in terms of ease of use and understanding of kano's results and this result will contribute to the further development of the attractive quality theory that enables to understand both the customers explicit and implicit needs.

• Magazine of the Korea Concrete Institute
• /
• v.8 no.6
• /
• pp.235-243
• /
• 1996

The mechanical behavior ot concrete is strongly influenced by various scenarios of crack initiation and crack propagation. Recently. the study of the interface fracture and cracking in interfacial regions is emerged as an important field, in the context of the developement of high performance concrete composites. The crack path criterion for elastically homogeneous materials is not valid when the crack advances at an interface because. in this case, the consideration of the relative magnitudes of the fracture toughnesses between the constituent materials and the interface are involved. In this paper, a numerical method is presented to obtain the values of two interfacial fracture parameters such as the energy release rate and the phase angle at the tip of an existing interface crack. Criteria based on energy release rate concepts are suggested for the prediction of crack growth at the interfaces and an hybrid experimental-numerical study is presented on the two-phase beam composite models containing interface cracks to investigate the cracking scenarios in interfacial regions. In general, good agreement between the experimental results and the prediction from the criteria is obtained.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.22 no.3
• /
• pp.287-293
• /
• 2012

This paper presents an efficient image registration method by measuring the similarity, which is based on multi-dimensional intensity fluctuation. Multi-dimensional intensity which considers 4 directions of the image, is applied to reflect more properties in similarity decision. And an intensity fluctuation is also applied to measure comprehensively the similarity by considering a change in brightness between the adjacent pixels of image. The normalized cross-correlation(NCC) is calculated by considering an intensity fluctuation to each of 4 directions. The 5 correlation coefficients based on the NCC have been used to measure the registration, which are total NCC, the arithmetical mean and a simple product on the correlation coefficient of each direction and on the normalized correlation coefficient by the maximum NCC, respectively. The proposed method has been applied to the problem for registrating the 22 face images of 243*243 pixels and the 9 person images of 500*500 pixels, respectively. The experimental results show that the proposed method has a superior registration performance that appears the image properties well. Especially, the arithmetical mean on the correlation coefficient of each direction is the best registration measure.

• Journal of Technologic Dentistry
• /
• v.16 no.1
• /
• pp.78-104
• /
• 1994

Under the fee for service schedule of Korean health insurance system, rational fee for dental laboratory products based on the cost is required to be formulated. The purpose of this study was to find actual cost of dental laboratory products in case of a University Hospital. Materials of this study were used as follows : 1. Balance sheet at Dec. 31, 1992 and profit and loss report of the year 1992 of the sample hospital 2. Performance report of dental laboratory department. 3. Purchasing and other accounting bills of dental laboratory materials. The following methods were used. 1. Actual cost finding of dental laboratory department was performed. 2. Work sampling methods were used for measuring standard working time by the process of working. 3. To porcelain fused to metal crown(non-precious), Relative value of the cost of dental laboratory products was calculated as 1.00. 4. Fee and cost of those products were compared on the basis of Relative values. The results of the study can be summarized as follow : 1. Overall, it took longs time than other items. to product denture-related items. 2. When several teeth are made in a time, average production time is much sorter than when one tooth is made in a time. 3. The relative price cost of Dicor cast crown and denture related items are higher than the criterion items. 4. The material cost occupies average 11% out of the total price cost, proportion of personnel expenses is average as 60.0%. 5. Some of the components consisting of the price cost are not reflected adequately in setting the level of the reimbursement price. 6. Relative values of dental laboratory products price cost are varied in the range from 0.05 to 2.83, overall, the reimbursement price of dental products appears not to reflect adequately the price cost. On the basis of this study results, the following ideas would be suggested : 1. Fee Schedule of dental laboratory products should be renovated in order to reflect their costs. 2. Dental laboratory product manufacturers should be enlarged for the economy of scale which may be useful for cost- containment. 3. Dental laboratory producters themselves are required to be standardiqed according to the categories of skill.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.40 no.12
• /
• pp.1080-1085
• /
• 2012

In this paper a sharp-edged type damping orifice for an aircraft door damper were designed, where the dynamic viscosity of working fluid were assumed to change up to 400cSt. The discharge coefficient of the damping orifice were investigated by CFD analyses and experiments. In particular, the influences of orifice diameter, edge angle, flow direction and the Reynolds number were taken into consideration. Based on this, it has been deduced how high Coulomb friction forces of damper seals is to be allowed to meet the performance criterion with respect to the orifice size.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.4
• /
• pp.1565-1574
• /
• 2011

Scheduling of die casting is a procedure of determining quantities of cast products so as to optimize a predetermined performance criterion. This paper presents a novel scheme of preventing product shortage raised by defective castings when die casting scheduling is applied to real casting operations. The previously developed linear programming (LP) model for die casting scheduling maximizes the average efficiency of melting furnaces in regard of the usage of molten alloy. However, the LP model is not able to cope with the problem of defective products occurring in the casting process. The proposed scheme is that whenever defective products are found in a shift, the foundryman produces additional cast products using the residue of molten alloy left at the end of the next shift. Neither the calculated amount of molten alloy nor the scheduling result of the LP model does not have to be altered for this method. The simulation result demonstrates the superiority and applicability of the newly proposed scheme.