• Bulletin of the Korean Mathematical Society
• /
• v.58 no.2
• /
• pp.461-479
• /
• 2021

This paper includes a general version of Bessel multipliers in Hilbert C∗-modules. In fact, by combining analysis, an operator on the standard Hilbert C∗-module and synthesis, we reach so-called generalized Bessel multipliers. Because of their importance for applications, we are interested to determine cases when generalized multipliers are invertible. We investigate some necessary or sufficient conditions for the invertibility of such operators and also we look at which perturbation of parameters preserve the invertibility of them. Subsequently, our attention is on how to express the inverse of an invertible generalized frame multiplier as a multiplier. In fact, we show that for all frames, the inverse of any invertible frame multiplier with an invertible symbol can always be represented as a multiplier with an invertible symbol and appropriate dual frames of the given ones.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.14 no.1
• /
• pp.115-121
• /
• 2010

Purpose: The purpose of this study is to measure F-18 FDG with two different types of dose calibrator measuring radionuclide and radioactivity and investigate the effect of F-18 FDG on SUV (Standard Uptake Value) in human body. Materials and Methods: Two different dose calibrators used in this study are CRC-15 Dual PET (Capintec) and CRC-15R (Capintec). Inject 1 mL, 2 mL, 3 mL of F-18 FDG into three 2 mL syringes, respectively, and measure initial radioactivity from each dose calibrator. Then measure and record radioactivity at 30 minute interval for 270 minutes. According to the initial radioactivity, linearity between decay factor driven from radioactive decay formula and the values measured by dose calibrator have been analyzed by simple linear regression. Fine linear regression line optimizing values measured with CRC-15 through regression analysis on the basis of the volume of which the measured value is close to the most ideal one in CRC-15 Dual PET. Create ROI on lung, liver, and region part of 50 persons who has taken PET/CT test, applying values from linear regression equation, and find SUV. We have also performed paired t-test to examine statistically significant difference in the radioactivity measured with CRC-15 Dual PET, CRC-15R and its SUV. Results: Regression analysis of radioactivity measured with CRC-15 Dual PET and CRC-15R shows results as follows: in the case 1 mL, the r statistic representing correlation was 0.9999 and linear regression equation was y=1.0345x+0.2601; in 2 mL case, r=0.9999, linear regression equation y=1.0226x+0.1669; in 3 mL case, r=0.9999, linear regression equation y=1.0094x+0.1577. Based on the linear regression equation from each volume, t-test results show significant difference in SUV of ROI in lung, liver, region part in all three case. P-values in each case are as follows: in 1 mL case, lung, liver and region (p<0.0001); in 2 mL case, lung (p<0.002), liver and region (p<0.0001); in 3 mL case, lung (p<0.044), liver and region (p<0.0001). Conclusion: Radioactivity measured with CRC-15 Dual PET, CRC-15R, dose calibrator for F-18 FDG test, do not show difference correlation, while these values infer that SUV has significant differences in the aspect of uptake in human body. Therefore, it is necessary to consider the difference of SUV in human body when using these dose calibrator.

• Journal of Korean Society of Water and Wastewater
• /
• v.28 no.3
• /
• pp.287-297
• /
• 2014

It is important to predict chlorine decay with different water purification processes and distribution pipeline materials, especially because chlorine decay is in direct relationship with the stability of water quality. The degree of chlorine decay may affect the water quality at the end of the pipeline: it may produce disinfection by-products or cause unpleasant odor and taste. Sand filtrate and dual media filtrate were used as influents in this study, and cast iron (CI), polyvinyl chloride (PVC), and stainless steel (SS) were used as pipeline materials. The results were analyzed via chlorine decay models by comparing the experimental and model parameters. The models were then used to estimate rechlorination time and chlorine decay time. The results indicated that water quality (e.g. organic matter and alkalinity) and pipeline materials were important factors influencing bulk decay and sand filtrate exhibited greater chlorine decay than dual media filtrate. The two-component second-order model was more applicable than the first decay model, and it enabled the estimation of chlorine decay time. These results are expected to provide the basis for modeling chlorine decay of different water purification processes and pipeline materials.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.3 no.1
• /
• pp.31-46
• /
• 1978

Consider a time interval during which the demand for trips is fixed (e.g. the rush hour period). The traveller has a choice between various public modes, whose travel times and fares are fixed, and the automobile mode, for which travel time and cost depend on the volume of traffic flow on those roads, which are subject to congestion. We consider the equilibrium in terms of a representative travellerm, who choses for any trip the mode and route with the least combined money and time cost. When several (parallel) model or routes are chosen, then the combined cost of money and time must be equal among these. Our problem is first, to find the optimal flows of cars and of public mode carriers on the various links of their networks and second the optimal fares for trips by the variousmodes. The object is to minimize the total operating costs of the carriers and car plus the total time costs to travellers. The optimal fares are related to, but not identical with the dual variables of the underlying Nonlinear Program. They are equal to these dual variables only in the case, when congestion tolls on trips or on the use of specific roads are collected from automobile users. When such tolls are not collected, they must be passed on as subsidies to travellers using competing modes. The optimal fares of public modes are then reduced by the amounts of these subsidies. Note that subsidies are not a flat payment to public carriers, but are calculated on the basis of tickets sold. Fares and subsidies depend in general on tile period considered. They will be higher during periods of higher demand. When the assumption of fixed trip demand is relaxed, this tare system is no longer best, but only second best since too much traffic will, in general, be generated. The Free Rider Theorem states the following : Suppose road tolls can be charged, so that a best pricing system for public modes is posssible. Then there may exist free rides on some routes and modes, but never on a complete round trip.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.35 no.9
• /
• pp.799-804
• /
• 2007

The behavior of spray emanating from an injector to be employed in a liquid-propellant thrust chamber is investigated by optical measurement techniques. The injector has eight holes, each of which has 30 cant angle from the center-axis with the diameter of 0.406 mm. In order to examine an atomization process according to the spray-generation conditions and the evolution along spray downstream, variational features in the velocity and size of droplets obtained through Dual-mode Phase Doppler An 799emometry (DPDA) are delineated and discussed together with instantaneous plane images captured by using Nd:Yag laser sheet beam. A categorization of spray-flow regime representing the atomization and turbulent nature is made through evaluating the non-dimensional parameters, i.e., Reynolds number and Weber number based upon the theoretical injection velocity. These qualitative and quantitative data of spray breakup will be a firm basis for the design of brand-new thruster

• The Journal of Korean Medicine
• /
• v.36 no.1
• /
• pp.61-74
• /
• 2015

Objectives: The main purpose of this study is to find a solution for modernized classification of herbal medicinal preparations in dual medical systems. Through this study, we expect to provide a reasonable foundation of herbal medicine for public health. Methods: We studied legal or technical terms of herbal medicinal preparations from the past regulations, and through this procedure, we could suggest clear definitions of terms for herbal medicinal preparations. We also investigated documents for approval of herbal medicinal preparation from US, EU(European union), The People's Republic of China, Japan, so that we can refer to them to revise regulation for appropriate use of herbal preparations. Results: In Korea pharmaceutical affairs act, any basis of 'Crude drugs' does not exist. But in some subordinary notifications, the way that they use the 'Natural product medicine' is used as a means of limiting basic rights of doctor or pharmacist of Korean medicine compared to doctor or pharmacist. At the same time, in subordinary notifications, provisions are vague and not enough for scientific evidence of Korean medicine. Thus, we re-categorized herbal medicinal preparations into new drugs, drugs made from herbal medicinal preparations and suggested requirements for drug approval. Conclusions: Instead of using the term 'Crude drug preparations', and we should use term 'Herbal medicinal preparations' in related act and notification. And also we suggest to amend subordinary regulations and documents for approval of herbal medicinal preparations. Through this, we can make herbal medicinal preparations be more industrialized.

• Journal of the Korea Concrete Institute
• /
• v.25 no.2
• /
• pp.175-185
• /
• 2013

Currently in precast concrete construction, precast concrete and cast-in-place concrete with different concrete strengths are used. However, current design codes do not provide shear design methods for PC-CIP hybrid members using dual concrete strengths. In the present study, the shear strengths of beams using dual concrete compressive strengths (24 MPa, 60 MPa) were tested. The test variables were the area ratio of the two concretes, longitudinal bar ratio, and shear span-to-depth ratio. The shear strengths of test specimens were evaluated by current design methods, using an effective concrete strength (considering the area ratio of the two concrete strengths). The test result showed that when 60 MPa concrete was used in the compressive zone and the longitudinal bar ratio was low, the shear strengths of the test specimens were less than the predictions. On the basis of the results, design recommendations were provided for the shear design of the PC-CIP hybrid beams.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.15 no.1
• /
• pp.39-48
• /
• 2011

In this present study, a response modification factor for a lightweight steel panel-modular system which is not clarified in a current building code was proposed. As a component of the response modification factor, an over-strength factor and a ductility factor were drawn from the nonlinear static analysis curves of the systems modeled on the basis of the performance tests. The final response modification factor was then computed by modifying the previous response modification factor with a MDOF (Multi-Degree-Of-Freedom) base shear modification factor considering the MDOF dynamic behaviors. As a result of computation for the structures designed as a dual frame system, ranging from 2-story to 5-story, the value of 4 was estimated as a final response modification factor for a seismic design, considering the value of 5 as an upper limit of the number of stories.

• Safety and Health at Work
• /
• v.8 no.1
• /
• pp.77-83
• /
• 2017

Background: In contemporary China, most parents are dual-earner couples and there is only one child in the family. We aimed to examine the associations of parents' work stress with suicidal ideation among the corresponding adolescent. We further hypothesized that low parental support experienced by adolescents may mediate the associations. Methods: Cross-sectional data from school students and their working parents were used, with 907 families from Kunming City, China. Stress at work was measured by the effort-reward imbalance questionnaire. Perceived parental support was assessed by an item on parental empathy and their willingness to communicate with the adolescent. Suicidal ideation was considered positive if students reported thoughts about suicide every month or more frequently during the previous 6 months. Logistic regression was used to examine the associations. Results: We observed that parents' work stress was positively associated with low parental support, which was in turn associated with adolescent suicidal ideation. The odds ratio for parents' work stress and adolescent suicidal ideation was 2.91 (95% confidence interval: 1.53-5.53), and this association was markedly attenuated to 2.24 (95% confidence interval: 1.15-4.36) after additional adjustment for parental support. Notably, mothers' work stress levels exerted stronger effects on children's suicidal ideation than those of fathers. Conclusion: Parents' work stress (particularly mother's work stress) was strongly associated with adolescent's suicidal ideation, and the association was partially mediated by low parental support. These results need to be replicated and extended in prospective investigations within and beyond China, in order to explore potential causal pathways as a basis of preventive action.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.5
• /
• pp.1778-1790
• /
• 2018

Based on the requirements and characteristics of multi-zone autonomous decision-making in modern power system, fully distributed computing methods are needed to optimize the economic dispatch (ED) problem coordination of multi-regional power system on the basis of constructing decomposition and interaction mechanism. In this paper, four fully distributed methods based on alternating direction method of multipliers (ADMM) are used for solving the ED problem in distributed manner. By duplicating variables, the 2-block classical ADMM can be directly used to solve ED problem fully distributed. The second method is employing ADMM to solve the dual problem of ED in fully distributed manner. N-block methods based on ADMM including Alternating Direction Method with Gaussian back substitution (ADM_G) and Exchange ADMM (E_ADMM) are employed also. These two methods all can solve ED problem in distributed manner. However, the former one cannot be carried out in parallel. In this paper, four fully distributed methods solve the ED problem in distributed collaborative manner. And we also discussed the difference of four algorithms from the aspects of algorithm convergence, calculation speed and parameter change. Some simulation results are reported to test the performance of these distributed algorithms in serial and parallel.