• The KSFM Journal of Fluid Machinery
• /
• v.17 no.5
• /
• pp.78-82
• /
• 2014

This paper describes a brief aerodynamic design procedure of multi-stage axial turbine. The design procedure was established including one dimensional scratch design, through flow analysis with empirical correlations, two dimensional airfoil design and three dimensional airfoil stacking. Detailed aerodynamic performance assessment was done with full three dimensional CFD method at the design and off design conditions to construct turbine performance map. With the present method, aerodynamic design procedure of 1st and 2nd stages of high pressure turbine for 10,000lbf class turbofan engine was introduced.

• Proceedings of the KIEE Conference
• /
• 1996.07b
• /
• pp.871-874
• /
• 1996

It is practically very important in multi-criteria long-tenn IRP process to develop the set of candidate resource plans that meet following two conditions. First, the number of resource plans should not be too large for computer job. Second, the unknown best plan should exist among the set of candidate plans. In this paper, several novel procedures are developed. The main idea of the procedures is the two-stage approach. The first stage is to find the set of feasible resource capacity mixes in given target year(s). And, the second stage is to find the set of alternative paths of resource options for each resource mix determined in the first stage.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.501-506
• /
• 2002

In this study, a novel systematic design procedure by Genetic Algorithm of a two stage relief valve is proposed. First of all. a mathematical model describing the dynamics of a balanced piston type relief valve has been derived. Governing equations such as dynamic equations for the main spool and the pilot spool and flow equations for each orifice are established. The mathematical model is verified by comparing the results of simulation with that of experiments. Furthermore, influences of the parameters on the dynamic characteristics of a relief valve have been investigated by simulation of the proposed model. Major design parameters on the valve response are determined, which affect the system response significantly. And then, using the determined parameters, the optimization of the two stage relief valve by Genetic Algorithm, which is a random search algorithm can find the global optimum without converging local optimum, is performed. The optimal design process of a two stage relief valve is presented to determine the major design parameters. Fitness function reflects the changing pressure according to parameters. It is shown that the genetic algorithms satisfactorily optimized the major design parameters of the two stage relief valve.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.19 no.39
• /
• pp.243-254
• /
• 1996

In this study, a model and an analysis method for parameter design is presented a linear relation between the input signal and the ideal value of a performance characteristic. Furthermore, There presented a new performance measure, expected quality loss after adjustment, which is proved to be equivalent to Taguchi's SN ratio approximately. On the basis of this, a two-step optimization procedure is proposed for parameter design considering the signal factor and the quality characteristics with continuous variable. Proposed procedure and Taguchi two-stage procedure are compared.

• Journal of Korean Dental Science
• /
• v.13 no.2
• /
• pp.67-72
• /
• 2020

Purpose: This clinical study presented the effectiveness of 2-stage posterior maxillary segmental osteotomy (PMSO) under local anesthesia in gaining interarch space to restore the posterior mandibular segment with dental implants. Materials and Methods: Nine patients who received two-stage PMSO for mandibular implant placement from 2003 to 2011 were included in the study. Of the 9 patients, 7 were female and 2 were male. Ages ranged form 28 to 72 (mean 46.6). Potential complications were investigated such as sinus infection, survival of bone segment, inflammatory root resorption of adjacent teeth, relapse of bone segment and timing of implant placement, delivery of implant prosthesis and stability of bone segment. Result: None of the patients showed relapse or complication. Bone segments were stabilized by opposed implant prosthesis. Conclusion: Office-based 2-stage PMSO under local anesthesia can be considered a stable and predictable procedure. Also pedicle damage can be avoided by allowing favor of blood supply to the bone segments. From these advantages, it can be concluded that this surgical procedure can decrease post-operative complications.

• IE interfaces
• /
• v.13 no.2
• /
• pp.273-280
• /
• 2000

Time-tradeoff measures and healthy years equivalents were assessed and compared through an empirical study based on Multi-attribute utility theory. The study included 33 student subjects as a pilot study, and 54 end-stage renal disease patients in Wisconsin. The two outcome measures were compared with the survival duration of 1, 5, and 10 years. The results of the study show that the time-tradeoff method and the two-stage method did not lead to the same numerical quantities, although they aim to measure the same quantities (equivalent numbers of healthy years) theoretically. The healthy years equivalents involved more inconsistencies, and were less reliable than the time-tradeoff measures. Overestimation of the healthy years equivalents was observed. This seemed to be caused by the complex procedure of the two-stage method as well as by the preferences assessment biases. Based on the study experiences, the time-tradeoff measure would be recommended for problems involving generic medical applications and health policies.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.30 no.10 s.253
• /
• pp.1320-1327
• /
• 2006

Parallel procedure and performance of two-step Eulerian code have not been reported sufficiently yet even though it was developed and utilized widely in the impact simulation. In this study, parallel strategy of two-step Eulerian code was proposed and described in detail. The performance was evaluated in the self-made linux cluster computer. Compared with commercial code, a relatively good performance is achieved. Through the performance evaluation of each computation stage, remap is turned out to be the most time consuming part among the other part such as FE processing, communication, time marching etc.

• Archives of Plastic Surgery
• /
• v.32 no.3
• /
• pp.281-286
• /
• 2005

The goal in facial paralysis treatment is to achieve the normal appearance of the face as well as to reconstruct the natural symmetrical smile. In cases of facial paralysis, a widely accepted procedure is the two stage method, which combines neurovascular free muscle transfer with cross face nerve grafting. Although the results are promising, the two operations of this method, which are about 1 year apart, impose an economic burden on the patients and require a lengthy period before results are obtained. In order to overcome these drawbacks, one stage method, using latissimus dorsi neurovascuular free muscle flap was introduced. Between January 2000 and January 2004, fifteen patients with long standing facial paralysis were treated in the Korea University Anam Hospital. The segmental latissimus dorsi with long nerve and pedicle was transferred to the paralyzed side of the face. The first postoperative movement of the transferred muscle was reported at 8.9 months, faster than that of the two stage method. During the next 24 months, a constant increase in the power of muscle contraction was observed. The fifteen cases were evaluated within an average of 31.7 months following the surgery and satisfactory results including muscle contraction were obtained in eleven of the cases but muscle contraction was not found in three cases.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.1006-1011
• /
• 2003

In this study, a novel systematic design procedure by Genetic Algorithm of a two stage relief valve is proposed. First of all, a mathematical model describing the dynamics of a balanced piston type relief valve has been derived. Governing equations such as dynamic equations for the main spool and the pilot spool and flow equations for each orifice are established. The mathematical model is verified by comparing the results of simulation with that of experiments. Furthermore, influences of the parameters on the dynamic characteristics of a relief valve have been investigated by simulation of the proposed model. Major design parameters on the valve response are determined, which affect the system response significantly. And then, using the determined parameters, the optimization of the two stage relief valve by Genetic Algorithm, which is a random search algorithm can find the global optimum without converging local optimum, is performed. The optimal design process of a two stage relief valve is presented to determine the major design parameters. Fitness function reflects the changing pressure according to parameters. It is shown that the genetic algorithms satisfactorily optimized the major design parameters of the two stage relief valve.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.3
• /
• pp.1243-1263
• /
• 2018

The two-stage linear discrimination analysis (TSLDA) is a feature extraction technique to solve the small size sample problem in the field of image recognition. The TSLDA has retained all subspace information of the between-class scatter and within-class scatter. However, the feature information in the four subspaces may not be entirely beneficial for classification, and the regularization procedure for eliminating singular metrics in TSLDA has higher time complexity. In order to address these drawbacks, this paper proposes an improved two-stage linear discriminant analysis (Improved TSLDA). The Improved TSLDA proposes a selection and compression method to extract superior feature information from the four subspaces to constitute optimal projection space, where it defines a single Fisher criterion to measure the importance of single feature vector. Meanwhile, Improved TSLDA also applies an approximation matrix method to eliminate the singular matrices and reduce its time complexity. This paper presents comparative experiments on five face databases and one handwritten digit database to validate the effectiveness of the Improved TSLDA.