• 대한산업공학회지
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• 제34권1호
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• pp.32-41
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• 2008

This paper studies a joint EOQ and EPQ model in which a stationary demand can be satisfied by recycled products as well as newly purchased products. The model assumes that a fixed quantity of the used products are collected from customers and later recovered for reuse. The recovered products are regarded as perfectly new ones. We also assume that the number of orders for newly purchasing items and the number of recovery setups in a cycle can be mutually independent integers. Under these assumptions, we develop an optimization model obtaining the economic order quantity for newly procured products, the optimal lot size for the recovery process, and the sequence of the orders and the setups, simultaneously. And then a simple solution procedure to find a local optimal control parameter set is proposed. To validate the model and the solution procedure, finally, some computational experiments are presented.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.472-477
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• 2017

In this work, the current limiting and recovery characteristics of a flux-lock type superconducting fault current limiter (SFCL) with series connection of two coils were effectively improved by adding a third winding into the conventional flux-lock type SFCL with series connection of two coils. To confirm the contribution of the third winding to the current limiting and recovery characteristics of this type of the SFCL, short-circuit testing was carried out with consideration of the third winding, and the effect of the third winding on the current limiting and recovery characteristics was examined by comparative analysis of the amplitude of the limited fault current and the power burden of the high-TC superconducting (HTSC) element comprising the SFCL. Through the analysis of both the limiting impedance and the operational current as the main design parameter of the SFCL, the improved current limiting and recovery characteristics of the flux-lock type SFCL using the third winding could be verified.

• 지역연구
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• 제34권1호
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• pp.3-17
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• 2018

본 논문은 임대료시장의 주기변화에 따른 헤도닉 모형의 임대료 결정요인의 영향력 변화를 분석하였다. 임대료지수를 구축하여 분석한 결과 금융위기가 전환점이 되어 서울시 임대료 시장이 하락기와 상승기로 구분됨을 밝혔으며 주기에 따른 헤도닉 모형의 특성변수의 회귀모수 변화를 고찰하였다. 분석은 강남오피스와 도심오피스로 구분하여 실시하였으며 권역에 상관없이 일관된 변화를 보인 개별회귀모수로서는 토지가격, 지하철역에서의 거리, 건물규모, 건물연한 및 전환이율로 밝혀졌다. 상승기에는 건물의 규모가 클수록 임대료가 높아지는 경향이 있으며 건물이 오래될수록 임대료 하락요인으로의 영향이 커지는 경향이 있는 것으로 나타났다. 전환이율 역시 임대료에서 차지하는 비중이 상승기에 높아짐을 보여준다. 토지가격의 영향은 줄어들고 교통편의성의 장점은 약해지고 있어 상승기에는 지리적 이점의 영향력이 감소하고 건물 특성의 영향력이 상대적으로 커지는 실증적 증거를 제시하였다.

• Journal of Yeungnam Medical Science
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• 제40권3호
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• pp.252-258
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• 2023

Background: The purpose of this study was to investigate whether postoperative cystography findings can predict early and longterm recovery from incontinence after radical prostatectomy (RP), compared with the other cystography parameters. Methods: I retrospectively reviewed 118 patients who underwent robot-assisted RP (RARP) for localized prostate cancer at single institution between January 2016 and April 2021. One hundred and seven patients were included in the study. Postoperative cystography was routinely performed 7 days after surgery. The bladder neck to pubic symphysis ratio, vesicourethral angle, and bladder neck anteroposterior length (BNAP) ratio (the bladder neck-posterior margin distances divided by the anteroposterior lengths) were evaluated. Continence was defined as cessation of pad use. The association between these variables and urinary incontinence was also analyzed. Results: The urinary incontinence recovery rates 1, 3, 6, and 12 months after RARP were 43.92%, 66.35%, 87.85%, and 97.19%, respectively. Multivariate logistic regression analysis demonstrated that a lower BNAP ratio and wider vesicourethral angle were significantly associated with continence restoration at 1, 3, and 6 months after surgery. In addition, in terms of days of pad usage, lower BNAP ratio, wider vesicourethral angle, and bladder neck preservation were significantly associated with recovery from urinary incontinence within 12 months as assessed by Cox proportional hazard analysis. Conclusion: This study demonstrated that vesicourethral angle and BNAP ratio were independent predictors of early recovery from post-prostatectomy incontinence. I suggest that both the sagittal and coronal views of postoperative cystography help anticipate early continence restoration after RARP.

• 대한기계학회논문집
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• 제18권8호
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• pp.2167-2176
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• 1994

This paper presents some useful design criteria for the turbine cogeneration system through both the design and off-design analysis. Comparative analysis of the part load performance is carried out for several gas turbines which have different design parameters represented by the turbine inlet temperature and pressure ratio. It is shown that the variation in part load efficiency considerably depends on the design parameter. The off-design operation of the heat recovery steam generator is simulated by introducing adequate assumptions for the heat transfer process. It is turned out that the design parameters of heat recovery steam generator should be determined by considering the favorable operation at the off-design conditions.

• ALGAE
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• 제32권4호
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• pp.325-336
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• 2017

Intertidal community recovery and resilience were investigated with quantitative and qualitative perspectives as a function of disturbance timing. The study was conducted in a lower intertidal rock bed of the southern coast of South Korea. Six replicates of artificial disturbance of a $50cm{\times}50cm$ area were made by clearing all visible organisms on the rocky substrate in four seasons. Each of the seasonally cleared plots was monitored until the percent cover data reached the control plot level. There was a significant difference among disturbance timing during the recovery process in terms of speed and community components. After disturbances occurred, Ulva pertusa selectively preoccupied empty spaces quickly (in 2-4 months) and strongly (50-90%) in all plots except for the summer plots where non-Ulva species dominated throughout the recovery period. U. pertusa acted as a very important biological variable that determined the quantitative and qualitative recovery capability of a community. The qualitative recovery of communities was rapid in summer plots where U. pertusa did not recruit and the community recovery rate was the lowest in winter plots where U. pertusa was highly recruited with a long duration of distribution. In this study, U. pertusa was a pioneer species while being a dominant species and acted as a clearly negative element in the process of qualitative recovery after disturbance. However, the negative effect of U. pertusa did not occur in summer plots, indicating that disturbance timing should be considered as a parameter in understanding intertidal community resilience in temperate regions with four distinct seasons.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2002년도 추계총회 및 연구발표회 초록집
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• pp.163.2-163
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• 2002

• 상하수도학회지
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• 제20권1호
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• pp.138-146
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• 2006

The characteristics of backwash and concentrate discharges depend upon the quality of the water being treated and the net recovery of the membrane system. This paper is to indicate a design methods on the capacities of residuals treatment facilities in membrane processes for drinking water. We operated a demonstration membrane plant with a recovery rate of 90% for designing G-water treatment plant. We investigated on design parameter (optimum coagulant dosage and surface loading rate etc.) to design efficiently the residuals treatment facilities. The settling test was conducted with 1m columns dosing PACl to kaolin and membrane residuals under the experimental condition that discharge permit was under a 60mg/L. When the quantity of membrane residuals was $1,575m^3/day$, the estimated results for 1st thickener demonstrated the surface loading rate of 14.4m/day, detention time of 5.83hr, available depth of 3.5m.

• 대한인간공학회지
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• 제7권2호
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• pp.31-44
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• 1988

If an error occurs in the automatic mode when the advanced teleoperator system performs a task in hostile environment then the automatic mode changes into the manual mode. The operation by the control program and the operation by a human recover the error in the manual mode. The system resumes the automatic mode and continues the given task. It is necessary to improve the manual mode in order to make the best use of a man-robot system, as a part of the human interface technique. Therefore, the error recovery task is performed by combining the operation by the control program representing autonomy of a robot and the operation by a human representing versatility of a human operator effectively in the view point of human factors engineering. The geometric inverse kinematics is used for the calculation of the robot joint values in the operation by the control program. The singularity operation error and the parameter operation error often occur in this procedure. These two operation errors increase the movement time of the robot and the coordinate reading time, during the error recovery task. A singularity algorithm, parameter algorithm and fuzzy control are studied so as to remove the disadvantages of geometric inverse kinematics. And the geometric straight line motion is studied so as to improve the disadvantages of the operation by a human.

• 조명전기설비학회논문지
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• 제16권6호
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• pp.30-39
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• 2002

본 논문에서는 전력동요 억제를 위한 TCSC의 강인한 LQG/LTR (Linear Quadratic Gaussian with Loop Transfer Recovery) 제어기 설계에 관한 연구를 하였다. LQG/LTR 제어기를 설계할 때 성능을 극대화하기 위해서는 여러 단계의 파라미터 조정을 하여야 한다. 이에 본 논문에서는 다 변수 LQG/LTR 안정화 제어기 선계를 체계적으로 할 수 있는 방법을 제안하였다. 설계된 제어기를 실제의 비선형 전력시스템에 적용함으로써 전력동요억제 효과를 검증하였다.