• The Transactions of the Korean Institute of Power Electronics
• /
• v.27 no.1
• /
• pp.33-39
• /
• 2022

A multi-phase brushless direct current (BLDC) motor is widely used in large-capacity electric propulsion systems such as submarines and electric ships. In particular, in the field of military submarines, the polyphaser motor must suppress torque ripple in various failure situations to reduce noise and ensure stable operation for a long time. In this paper, we propose a polyphaser current control method that can improve efficiency and reduce torque ripple by minimizing the increase in stator winding loss at maximum output torque by controlling the phase angle and amplitude of the steady-state current during open circuit failure of the stator winding. The proposed control method controls the magnitude and phase angle of the healthy phase current, excluding the faulty phase, to compensate for the torque ripple that occurs in the case of a phase open failure of the motor. The magnitude and phase angle of the controlled steady-state current are calculated for each phase so that copper loss increase is minimized. The proposed control method was verified using hardware-in-the-loop simulation (HILS) of a 12-phase BLDC motor. HILS verification confirmed that the increase in the loss of the stator winding and the magnitude of the torque ripple decreased compared with the open phase fault of the motor.

• Journal of the Korean Applied Science and Technology
• /
• v.30 no.4
• /
• pp.761-769
• /
• 2013

This study used HPLC to analyze the contents of catechins, alkaloids, theanine, total phenolic compounds and antioxidant activities of commercial Hadong green tea leaves(Uzen, Sezak, Jungzak, Daezak). The content of catechins, alkaloids, theanine, total phenolic compounds were lower by water extracts than by 80% ethanol-water extracts. Total catechin and alkaloid contents in Uzen(172.33 mg/g, 30.80 mg/g) by 80% ethanol extract were the highest. Theanine contents of 80% ethanol-water extracts ranged form 55.36 to 37.48 mg/g of tea leaves. Total phenloic compounds contents of green tea were higher than Uzen. Antioxidative of green tea by DPPH, FTC, TBA method were higher than that Uzen.

• The Journal of Korean Medicine
• /
• v.45 no.1
• /
• pp.182-201
• /
• 2024

Objectives: This study was conducted to develop a standard acupotomy consent form that takes into account the unique characteristics of Korean Medicine. The study was motivated by the increasing importance of patient autonomy and the growing number of legal disputes related to medical malpractice in the clinical field of Korean Medicine. Methods: The analysis phase of the study involved a survey of the current status of acupotomy consent forms in Korean Medicine hospitals nationwide. The items of each form were analyzed based on the contents of the Medical law and the standard contract for medical procedures of the Fair Trade Commission (FTC). In the development and evaluation phase, the items and contents of the acupotomy consent form were evaluated using a 5-point Likert scale and content validity was assessed through two rounds of Delphi surveys. In the improvement phase, the contents of the consent form were revised based on the results of a survey of inpatient and outpatient patients in the Department of Acupuncture and Moxibustion at Pusan National University Korean Medicine Hospital, and real-time online meeting. The final version of the standard acupotomy consent form was completed after undergoing proofreading and corrections by a linguistics expert. Results: Only 30% of Korean Medicine hospitals have implemented acupotomy consent forms. The items of the consent forms did not fully include the items presented in the Medical act and the standard contract for medical procedures of the FTC. To address this issue, two rounds of Delphi surveys and a real-time discussion were conducted with a panel of 12 experts on 27 preliminary items of consent forms. The items and contents that met the criteria for content validity ratio, convergence, and consensus were derived. Based on the derived items and content, a standard acupotomy consent form was developed. Conclusions: The standard consent form for acupotomy is anticipated to ensure patient autonomy and enhance transparency and liability in acupotomy. Furthermore, it is expected to serve as evidence in case of medical disputes related to acupotomy and contribute as a reference document for the development of standard consents forms for various procedures of Korean Medicine. However, the limitations of the study include that the survey of consent forms was limited to only training hospitals of Korean Medicine, and the standard consent form is only applicable to adults in Korea. Future studies are needed to address these limitations.

• KSBB Journal
• /
• v.26 no.5
• /
• pp.459-464
• /
• 2011

In this study, the canadian peat moss extract was purified by a supercritical ₂ using three different conditions and assessed its biological activities. Peat moss was extracted by acid-alkaline extraction method (sample 1) and purified by a supercritical $CO_2$ at $40^{\circ}C$ under pressure of 100 bar (sample 2), 120 bar (sample 3) or 150 bar (sample 4). We evaluated the antioxidant activities of the samples by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging, $Fe^{2+}$/ascorbate (FTC) and 2-thiobarbituric acid (TBA) methods. The antioxidant activities were examined by comparing the results with that of ascorbic acid as a positive control. Sample 3 showed relatively higher DPPH radical-scavenging activities than other samples. The antioxidant activity by FIC method exhibited similar results as the DPPH radical-scavenging activities. On the other hand, sample 2 showed higher antioxidant activity measured by TBA method of all. The whitening effects of the samples were examined using mushroom tyrosinase and B16F10 melanoma cells. Sample 3 exhibited overall significant whitening effects, however, other samples showed relatively lower effects. These results suggest that the peat moss extract purified by a supercritical ₂ could be used as a cosmetic ingredient for the anti-aging and whitening effects.

• Korean Journal of Plant Resources
• /
• v.21 no.1
• /
• pp.28-35
• /
• 2008

Several extracts of different parts and solvent fractions of Cornus kousa were obtained and their functional material contents, antioxidant activities and tyrosinase inhibition effects were determined. Content of total polyphenols and flavonoids contents in flower were 169.638 $mg{\cdot}g^{-1}$ and 25.418 $mg{\cdot}g^{-1}$, respectively, which were much higher than those of other parts. Also, flower extracts showed the strongest effects on DPPH and ABTS radicals scavenging and ferrous ion chelating. In flower, leaf, and stem extracts, inhibition effects on peroxidation of linoleic acid determined by ferric thiocyanate(FTC) method were higher than a synthetic antioxidant, BHT. Tyrosinase inhibition activities were shown only in flower extract. Flower and leaf extracts, showing high biological activities in various system, were successively reextracted with n-hexane, chloroform, ethylacetate and n-butanol. Total polyphenol contents of water fractions were higher than any other solvent fractions in both flower and leaf, 67.006 $mg{\cdot}g^{-1}$ and 67.739 $mg{\cdot}g^{-1}$, respectively. But total flavonoid contents were higher in ethyl acetate fraction for flower extract and butanol fraction for leaf extract. Among the solvent fractions, the highest efficiency of free radical scavenging activities was obtained in ethyl acetate fraction for flower extract and n-butanol fraction for leaf extract. Tyrosinase inhibition activities were higher in water fraction for both flower and leaf extracts, 49.24% and 31.8%, respectively.

• Journal of Distribution Research
• /
• v.17 no.1
• /
• pp.37-63
• /
• 2012

In franchise business, exclusive sales territory (sometimes EST in table) protection is a very important issue from an economic, social and political point of view. It affects the growth and survival of both franchisor and franchisee and often raises issues of social and political conflicts. When franchisee is not familiar with related laws and regulations, franchisor has high chance to utilize it. Exclusive sales territory protection by the manufacturer and distributors (wholesalers or retailers) means sales area restriction by which only certain distributors have right to sell products or services. The distributor, who has been granted exclusive sales territories, can protect its own territory, whereas he may be prohibited from entering in other regions. Even though exclusive sales territory is a quite critical problem in franchise business, there is not much rigorous research about the reason, results, evaluation, and future direction based on empirical data. This paper tries to address this problem not only from logical and nomological validity, but from empirical validation. While we purse an empirical analysis, we take into account the difficulties of real data collection and statistical analysis techniques. We use a set of disclosure document data collected by Korea Fair Trade Commission, instead of conventional survey method which is usually criticized for its measurement error. Existing theories about exclusive sales territory can be summarized into two groups as shown in the table below. The first one is about the effectiveness of exclusive sales territory from both franchisor and franchisee point of view. In fact, output of exclusive sales territory can be positive for franchisors but negative for franchisees. Also, it can be positive in terms of sales but negative in terms of profit. Therefore, variables and viewpoints should be set properly. The other one is about the motive or reason why exclusive sales territory is protected. The reasons can be classified into four groups - industry characteristics, franchise systems characteristics, capability to maintain exclusive sales territory, and strategic decision. Within four groups of reasons, there are more specific variables and theories as below. Based on these theories, we develop nine hypotheses which are briefly shown in the last table below with the results. In order to validate the hypothesis, data is collected from government (FTC) homepage which is open source. The sample consists of 1,896 franchisors and it contains about three year operation data, from 2006 to 2008. Within the samples, 627 have exclusive sales territory protection policy and the one with exclusive sales territory policy is not evenly distributed over 19 representative industries. Additional data are also collected from another government agency homepage, like Statistics Korea. Also, we combine data from various secondary sources to create meaningful variables as shown in the table below. All variables are dichotomized by mean or median split if they are not inherently dichotomized by its definition, since each hypothesis is composed by multiple variables and there is no solid statistical technique to incorporate all these conditions to test the hypotheses. This paper uses a simple chi-square test because hypotheses and theories are built upon quite specific conditions such as industry type, economic condition, company history and various strategic purposes. It is almost impossible to find all those samples to satisfy them and it can't be manipulated in experimental settings. However, more advanced statistical techniques are very good on clean data without exogenous variables, but not good with real complex data. The chi-square test is applied in a way that samples are grouped into four with two criteria, whether they use exclusive sales territory protection or not, and whether they satisfy conditions of each hypothesis. So the proportion of sample franchisors which satisfy conditions and protect exclusive sales territory, does significantly exceed the proportion of samples that satisfy condition and do not protect. In fact, chi-square test is equivalent with the Poisson regression which allows more flexible application. As results, only three hypotheses are accepted. When attitude toward the risk is high so loyalty fee is determined according to sales performance, EST protection makes poor results as expected. And when franchisor protects EST in order to recruit franchisee easily, EST protection makes better results. Also, when EST protection is to improve the efficiency of franchise system as a whole, it shows better performances. High efficiency is achieved as EST prohibits the free riding of franchisee who exploits other's marketing efforts, and it encourages proper investments and distributes franchisee into multiple regions evenly. Other hypotheses are not supported in the results of significance testing. Exclusive sales territory should be protected from proper motives and administered for mutual benefits. Legal restrictions driven by the government agency like FTC could be misused and cause mis-understandings. So there need more careful monitoring on real practices and more rigorous studies by both academicians and practitioners.

• Korean Journal of Food Science and Technology
• /
• v.37 no.2
• /
• pp.233-240
• /
• 2005

To discover new functional materials using edible plants, antioxidant activities of methanol extracts from various parts of seven wild vegetables were investigated in vitro. Total polyphenol contents, determined by Folin-Denis method, varied from 16.74 to $130.22{\mu}g/mg$. Radical-scavenging activities of methanol extracts were examined using ${\alpha},\;{\alpha}-diphenyl-{\beta}-pirrylhydrazyl$ (DPPH) radicals and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) assay. Inhibition effects on peroxidation of linoleic acid determined by ferric thiocyanate (FTC) method and on oxidative degradation of 2-deoxy-D-ribose in Fenton-type reaction system were dose-dependent. Athyrium acutipinulum Kodama (leaf and rood), Achyranthes japonica (Miq.) Nakai (seed), and Solidago virga-aurea var. gigantea Nakai (root) showed relatively high antioxidant activities in various systems.