• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.2
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• pp.65-73
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• 2018

The dynamic capabilities of sensing market signals, creating new opportunities and reconfiguring resources and capabilities to new opportunities in a rapidly changing economic environment determines the competitiveness of the enterprise to create added value and survival. This study conceptualized a two-stage performance measurement framework based on the casual model of resource (input)-process-performance (output). We have developed a 'Process capability index' that reflect the dynamic capabilities factors as a key intermediary product linking resource inputs and performance outputs in enterprise performance measurement. The process capability index consists of four elements : manpower (level of human resource), operation productivity, structure and risk management. The DEA (Data Envelopment Analysis) model was applied to the developed performance indicators to analyze the branch office performance of a telecom company. Process capability efficiency (stage 1) uses resource inputs to reach a certain level of process capabilities. In performance result efficiency (stage 2), the process capabilities are used to generate sales revenues and subscribers. The two-stage DEA model derives intermediate output values that optimize the individual stages simultaneously. Some branch offices in the telecom company have focused on process capability efficiency or some other branch offices focused on performance result efficiency. Positioning map using two-stage efficiency decomposition and benchmarking can help identify the sources of inefficiencies and visualize strategic directions for performance optimization. Applications of two-stage DEA in conjunction with the case study that are meaningfully used in performance measurement areas have been scarce. In particular, this paper has the contribution to present a new performance measurement model considering the organization theory, the dynamic capabilities.

• The Plant Pathology Journal
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• v.17 no.3
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• pp.128-140
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• 2001

Infection of pepper leaves by Colletotrichum cocodes at the two- and eight-leaf stages caused susceptible and resistant lesions 96 h after inoculation, respectively. At the two-leaf stage, progressive symptom development occurred on the infected leaves. In contrast, localized necrotic spots were characteristic symptoms at the eight-leaf stage. Infected leaves at the two-leaf stage exhibited cell death accompanied by the accumulation of autofluorescent compounds. At the eight-leaf stage, pepper leaves infected by the anthracnose fungus displayed localized autofluorescence from the symptoms. Infection of pepper leaves by C. cocodes at the two-leaf stage resulted in its rapidand massive colonization of all the leaf tissues including the vascular tissue, together with cytoplasmic collapse, distortion of chloroplasts, and disruption of host cell walls. However, penetration of C. cocodes was very limited in the older leaf tissues of pepper plants at the eight-leaf stage. Fungal hyphae grew only in the intramural spaces of the epidermal cell walls at this stage. Occlusion of amorphous material in xylem vessels, aggregation of fibrillar material in inter-cellular spaces, and deposition of protein bodies were found as resistance responses to C. cocodes.

• Archives of Plastic Surgery
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• v.32 no.1
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• pp.110-116
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• 2005

Male pseudohermaphroditism is individuals with Y chromosome whose external appearances fail to develop as expected as a normal male. Cytogenetic form of male pseudohermaphroditism was 46XY but external genital forms were variable. We reviewed data from 7 patients with male pseudohermaphroditism operated in Dong-A University Hospital from January 1996 to August 2002. They all had severe form of hypospadias (pseudovaginal perineoscrotal type). Only 1 of 7 cases was operated urethroplasty by one stage method, and all others by two stage method. Patients with mild chordee were operated by one stage method and patients with severe chordee were operated by two stage method. Complete chordee release was done by Z-plasty or FTSG on the first stage and posterior urethroplasty was done at level of mid-dorsum of shaft at the same time. Anterior urethroplasty was done completely on the second stage. Results were good from the viewpoint of shape and urination. Urethral fistula occurred in two cases, but other complications (infection, urethral stricture, etc.) didn't occur. In conclusion, two stage method was compatible to correct hypospadias in male pseudohermaphroditism, because hypospadias in male pseudohermaphroditism is in severe form.

• Smart Structures and Systems
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• v.17 no.4
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• pp.647-667
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• 2016

In this paper, dynamic displacement is estimated with high accuracy by blending high-sampling rate acceleration data with low-sampling rate displacement measurement using a two-stage Kalman estimator. In Stage 1, the two-stage Kalman estimator first approximates dynamic displacement. Then, the estimator in Stage 2 estimates a bias with high accuracy and refines the displacement estimate from Stage 1. In the previous Kalman filter based displacement techniques, the estimation accuracy can deteriorate due to (1) the discontinuities produced when the estimate is adjusted by displacement measurement and (2) slow convergence at the beginning of estimation. To resolve these drawbacks, the previous techniques adopt smoothing techniques, which involve additional future measurements in the estimation. However, the smoothing techniques require more computational time and resources and hamper real-time estimation. The proposed technique addresses the drawbacks of the previous techniques without smoothing. The performance of the proposed technique is verified under various dynamic loading, sampling rate and noise level conditions via a series of numerical simulations and experiments. Its performance is also compared with those of the existing Kalman filter based techniques.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.10
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• pp.2130-2141
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• 2002

A unique technique to estimate the magnitude or contribution ratio of each stage backlash in a system with a two-stage gear reducer is proposed. The concept to estimate the magnitude or contribution ratio of each stage backlash is based on the change of frequency response characteristic, in particular, the change of anti-resonant frequency and resonant frequency, due to the change of each stage backlash magnitude, even though the total backlash magnitude of a system with a two-stage gear reducer is constant. The validity of the technique is verified in a seeker gimbal and satisfactory results are obtained. It is thought that the diagnosis and maintenance of the manufacturing machines and systems with two-stage gear reducers will become more efficient and economical by virtue of the proposed technique.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.2
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• pp.191-196
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• 2010

Hybrid heat pumps, which combine the vapor compression and absorption heat pump cycle, can efficiently produce hot water of $80^{\circ}-90^{\circ}C$ from the low temperature of ${\sim}50^{\circ}C$. In this study, the performance of a two-stage hybrid heat pump (HHP) was compared with a single-stage hybrid heat pump using EES (Engineering Equation Solver). For the same operating conditions, the two-stage HHP showed a slightly higher COP (Coefficient Of Performance) and more stable operating conditions than the single-stage HHP. Moreover, the maximum working fluid temperature of the two-stage HHP was found to be lower than that of the single-stage HHP by about 40 K, which makes the working conditions of the lubricating oil safer. The COPs of both systems decreased with increasing UA-values. However, the heat output of the HHP was increased at the same time.

• Journal of Power System Engineering
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• v.19 no.6
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• pp.82-88
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• 2015

In this paper, cycle performance analysis of two-stage compression and one-stage expansion refrigeration system applied various refrigerants is presented to offer the basic design data for the operating parameters of the system. The operating parameters considered in this study include degree of superheating and subcooling, compressor efficiency, evaporation temperature, condensing temperature, mass flow rate ration into inter-cooler, effectiveness of internal heat exchanger. The main results were summarized as follows : The COP of two-stage compression and 1-stage expansion refrigeration system increases with the increasing subcooling, mass flow rate ration of inter-cooler, evaporation temperature, but decreases with the increasing condensing temperature and superheating degree. Therefore, subcooling degree, mass flow rate ratio of inter-cooler of two-stage compression and 1-stage expansion using substitute refrigerant have an effect on COP of this system. The COP of alternative refrigerants was higher than the COP of R22 in this study, although the COP of some mixed refrigerants were lower than COP of R22.

• Journal of the Korean Wood Science and Technology
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• v.43 no.1
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• pp.76-85
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• 2015

In this study, we investigated optimal reaction conditions for furfural production from lignocellulosic biomass by two-stage acid treatment. Furfural produced by this method was recovered using XAD-4 resin. Oxalic and sulfuric acid were used as catalysts for the first stage of treatment. The concentration of xylose in the hydrolysate obtained from the first stage was $18.86g/{\ell}$ with oxalic acid and $19.35g/{\ell}$ with sulfuric acid. The concentration of oligosaccharide was relatively high when sulfuric acid was used. Maximum yield of furfural, that is, 55.10% ($6.71g/{\ell}$), was obtained when oxalic acid was used for the first stage and $0.1m{\ell}$ of sulfuric acid was used for the second stage of treatment for 90 min. Furfural production yield increased with increasing the reaction time. Most of the furfural produced by this two-stage treatment method was recovered using XAD-4 resin.

• Communications for Statistical Applications and Methods
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• v.5 no.3
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• pp.895-904
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• 1998

Two stage shrinkage testimator is a kind of adaptive estimators based on a test on an initial estimate of parameter. Since weighing factor plays an important roll in assessing the properties of testimator, its choice is extremely crucial in two stage testimation. Adke, Waikar and Schuurmann(1987) proposed a testimator for the mean of an exponential distribution defined with their own weighing factor. Two alternative testimators obtained using changed weighing factors are presented, and their Mean squared error(MSE) formulae are provided in this paper. Their properties are compared with those of existing one by means of MSE.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.2
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• pp.136-146
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• 2022

Some surface defects make the weak quality of steel materials. To limit these defects, we advocate a one-stage detector model RetinaNet among diverse detection algorithms in deep learning. There are several backbones in the RetinaNet model. We acknowledged two backbones, which are ResNet50 and VGG19. To validate our model, we compared and analyzed several traditional models, one-stage models like YOLO and SSD models and two-stage models like Faster-RCNN, EDDN, and Xception models, with simulations based on steel individual classes. We also performed the correlation of the time factor between one-stage and two-stage models. Comparative analysis shows that the proposed model achieves excellent results on the dataset of the Northeastern University surface defect detection dataset. We would like to work on different backbones to check the efficiency of the model for real world, increasing the datasets through augmentation and focus on improving our limitation.