• Journal of the Korean Institute of Telematics and Electronics S
• /
• 제34S권1호
• /
• pp.105-114
• /
• 1997

The phase retrieval problem is concerned with the reconstruction of a signal or its fourier transform phase form the fourier transform magnitude of the signal. This problem does not have a unique solution, in general. If, however, the desired signal is minimum-phase, then it can be decided uniquely. This paper shows that we can make a minimum-phase signal by adding a delta function having a large value at the origin of an arbitrary one-dimensional signal, and a two-dimensional signal can be uniquely specified from its fourier transform magnitude if it is added by a delta function having a large value at the origin, and finally we can solve a two-dimensional phase retrieval problem by decomposing it into several ine-dimensional phase retrieval problems.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 한국건설관리학회 2006년도 정기학술발표대회 논문집
• /
• pp.355-360
• /
• 2006

Function analysis and idea creation phase in Value Engineering(VE) Process is applied to manufacturing Industry for developing functions for elements of products, and in construction come to use various components like process, size of project, spaces as well as function itself due to multi-functional aspect. For this reason, VE applications to the construction industry are considered to be less frequent and efficient than to the manufacturing. To resolve this problem, a new technique of Function Integration Fast(HI FAST) and Hierarchical Value Engineering Concept Modules(HVECM) was made for practical integration and sequence of VE job Plan. Two types of function would be defined In this method, first and second function, during the job Plan process, and two function champions be selected for next creation phase process. For verification of consecutiveness of function analysis and idea creation phase for successful VE project implementation, this methodology was tested under design phase in office and IT Multi-functional building project. Make sure the successful application of this process with this method, need to develop the talent of VE experts and team members for process of function analysis and creation phase.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• 제16권4호
• /
• pp.262-269
• /
• 2016

In this paper, we propose a novel dynamical love model of Romeo and Juliet, which has an external force with a fuzzy membership function. The external force used in the model has the characteristics of a Gaussian function. The chaotic behavior in the model is demonstrated using time series and phase portraits.

• Transactions of the Korean Society of Mechanical Engineers
• /
• 제14권5호
• /
• pp.1290-1299
• /
• 1990

Characteristics of flow patterns in horizontal gas-liquid two-phase flow for two different sizes of pipe were investigated based upon a statistical analysis of differential pressure fluctuations at an orifice. The probability density function and the power spectral density function of the traces indicate peculiar shapes depending upon the two-phase flow regime. Mixed and separated flows also could be identified by the autocorrelation function. The transition region from separated flow to mixed flow also could be identified by these statistical properties. The experimental data determined by this method were compared with the flow pattern maps suggested by other investigators. The result indicates that the statistical characteristics of differential pressure fluctuations at orifices may be a useful tool for identifying flow patterns of horizontal gas-liquid two-phase flow.

• Journal of the Korean Society of Propulsion Engineers
• /
• 제20권3호
• /
• pp.78-86
• /
• 2016

In this paper we propose a new frame transfer function model describing the variations of a heat release rate in response to an external flow oscillation in gas turbine systems. A critical difference of our model compared to the so-called $n-{\tau}$ model which has been widely used for a prediction of combustion instability (CI), is that our model is able to describe a nonlinear relation between phase and frequency. In contrast, the phase part of the $n-{\tau}$ model is a pure time delay and thus the phase should be a linear function of frequency, which is inconsistent with many experimental results of real combustion systems. For an illustration, our new model is applied to experimental data and the effect of phase nonlinearity is investigated in the context of combustion instability.

• The Korean Journal of Nuclear Medicine
• /
• 제19권2호
• /
• pp.43-50
• /
• 1985

With the improvement of hemodialysis, the course of the disease in patient with endstage renal disease has been clearly improved. Nevertheless, among several shortcomings to our present mode of renal replacement therapy, cardiovascular complications have been the leading cause of morbidity and mortality. Several factors such as anemia, arteriovenous shunting of blood, intermittent extracorporeal circulation and hypertension may be contributing. But little is known about the quantitative cardiac hemodynamic characteristics occurred during hemodialysis. The purpose of this study is to observe the sequential hemodynamic changes before, during and after the hemodialysis and to investigate reliable parameters in the detection of ventricular dysfunction. In the present study, equilibrium radionuclide cardiac angiography was performed and left and right ventricular volume indices, ejection phase indices of both ventricular, performance were measured in the 16 stable patients with chronic renal failure treated with maintenance hemodialysis sequentially i.e. before, during (early and late phase) and after the hemodialysis. The results obtained were as follows; 1) The indices of the left ventricular function were not changed during the hemodialysis but increased after the hemodialysis. 2) The indices of the right ventricular function(EF, SVI) were significantly decreased in the early phase (15, 30 minutes after starting extracorporeal circulation) but recovered after the hemodialysis. 3) The ratio of right ventricular to left ventricular ejection fraction was significantly decreased in the early phase and the lung volume indices were significantly increased at the same phase. As a conclusion, hemodialysis improves left ventricular function maybe due to increased contractility, and effects on the right ventricular function maybe due to the increased lung volume in the early phase of hemodialysis.

• Journal of Korean Academy of Nursing
• /
• 제29권3호
• /
• pp.467-484
• /
• 1999

The main objectives of this study were to investigate the concept of family function from the perspective of the contemporary Korean family, and to construct model of change of family function with chronic illness. The hybrid model approach was applied in which three phases(theoretical phase, empirical phase, and analytic phase) of concept development were explored for family functioning. The study was conducted from 1997 to 1998. In empirical phase, two groups of purposive samples were drawn : normal family group composed of six families without ill family member, and ill family group composed of seven families of which wives have rheumatoid arthritis. Only families with child(or children) in primary or secondary schools were included in the study. The results were as follows : In theoretical phase, six dimensions of family concept were emerged : affective, structural, control, cognitive, financial, and reproductive dimension. In order to analyse the Korean normal family function in middle class with middle-aged women, financial and reproductive dimension were not included. In empirical phase, five dimensions(affective, structural, control, cognitive, and external relationship) were found from the normal family data. External relationship dimension is very important factor as a resource of the support, especially when their parents or siblings had no help or support to them. In the affective dimension, Korean family emphasized harmony and balance rather than affective expression between couples and between parents and children. They also showed common goals of the families to solve their problems to control the family members. The priority of the goals was getting into the higher education of their children or helping their unhealthy parents or family members. Six dimensions (affective, structural, control, cognitive, external relationship, and financial) of family functions were emerged from the ill family data. From the analysis of ill family data, types of restructuring house chore after wives illness were developed : (a) negociated, (b) accomodated, and (c) isolated, enduring types. Although the dimensions of family functioning identified in this study are similar to the conceptualizations that exist in the western literature, there were distinct differences in the nature of major themes and subconcepts under these family function dimensions.

• Proceedings of the KIEE Conference
• /
• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
• /
• pp.456-458
• /
• 1997

The phase-lock technique is applied to a three-phase semi-bridge type battery charger system. Using an inner fast dynamic loop, the phase-locked voltage control (PLVC) technique of three-phase semi-bridge converter is proposed to give a frequency synchronism and to reduce the subharmonics due to the unbalance of transformer or power line. To protect the power devices, the two stage soft-start, function with softly locking the phase and softly increasing the current is presented. As limiting the reference voltage of the inner voltage control loop, muti-lock phenomena are removed on the PLVC loop. A current limit function is also proposed to limit the current of battery and converter. The proposed controller is confirmed through experiment results.

• Proceedings of the KIEE Conference
• /
• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(II)
• /
• pp.1243-1246
• /
• 1987

To characterize the biological tissues, the new methods to measure the frequency dependent attenuation are presented in this paper. In general, ultrasonic phase information was assumed by linear function of the frequency. But, the minimum phase function which characterizes the frequency dispersion of tissue was derived in [l]. It is very significant to measure the attenuation by using the minimum phase function to characterize the frequency dispersion of tissue. Therefore, a more efficient method measuring the frequency dependent attenuation are proposed by using the estimated sound velocity and polarity of reflected signal. To verify the algorithms, pulse reflection experiments are performed.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
• /
• pp.483-487
• /
• 1994

In this paper, we analize the effect of a steering water used in a unified phase I-phase II semi-infinite constrained optimization algorithm and present a new algorithm based on the facts that when the point x is far away from the feasible region where all the constraints are satisfied, reaching to the feasible region is more important than minimizing the cost function and that when the point x is near the region, it is more efficient to try to reach the feasible region and to minimize the cost function concurrently. Also, the angle between the search direction vector and the gradient of the cost function is considered when the steering parameter value is computed. Even though changing the steering parameter does not change the rate of convergence of the algorithm, we show through some examples that the proposed algorithm performs better than the other algorithms.