• Title, Summary, Keyword: Chopping

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Chopping Frequency Extraction of JEM Signal Using MUSIC Algorithm (MUSIC 알고리즘을 이용한 JEM 신호의 Chopping 주파수 추출)

  • Song, Won-Young;Kim, Hyung-Ju;Kim, Sung-Tai;Shin, In-Seon;Myung, Noh-Hoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.30 no.3
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    • pp.252-259
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    • 2019
  • Jet engine modulation(JEM) signals are widely used in the field of target recognition along with high-range resolution profile and inverse synthetic aperture radar because they provide specific information of the jet engine. To obtain the number of blades of the jet engine, the chopping frequency proportional to the number of blades must be extracted. In the conventional chopping frequency extraction method, an initial threshold value is defined and a method of detecting the chopping peak is used. However, this detection method takes time depending on the signal due to repetitive detection. Thus, in this study, we proposed to extract the chopping frequency using MUltiple SIgnal Classification(MUSIC) algorithm. We applied the MUSIC algorithm to a given JEM signal to find the chopping frequency and determine the blade number candidates. We also applied the MUSIC algorithm to other chopping frequency extractions to determine the score of the candidate groups. Unlike the conventional detection algorithm, which requires repetitive frequency detection, MUSIC algorithm quickly detects the accurate chopping frequency and reduces the calculation time.

A Design of Instrumentation Amplifier using a Nested-Chopping Technique (Nested-chopping 기법을 이용한 Instrumentation Amplifier 설계)

  • Lee, Jun-Gyu;Burm, Jin-Wook;Lim, Shin-Il
    • Proceedings of the KIEE Conference
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    • pp.483-484
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    • 2007
  • In this paper, we describe a chip design technique for instrumentation amplifier using a nested-chopping technique. Conventional chopping technique uses a pair of chopper, but nested chopping technique uses two pairs of chopper to reduce residual offset and 1/f noise. The inner chopper pair removes the 1/f noise, while the outer chopper pair reduces the residual offset. Our instrumentation amplifier using a nested chopping technique has residual offset under 100 nV. We also implement very low frequency filter. Since this filter needs very large RC time constant, we use a technique named 'diode connected PMOS' to increase R with small die area. The total power consumption is 3.1 mW at the supply voltage of 3.3V with the 0.35um general CMOS technology. The die area of implemented chip was $530um{\times}300um$.

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Sanitation Assessment and Microbiological Analysis of the Domestic Kitchen Utensils (가정 내 주방용품 및 기구의 위생실태 및 미생물학적 분석)

  • Kang, Myong-Suk;Chang, Yun-Hee
    • Korean journal of food and cookery science
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    • v.24 no.5
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    • pp.706-712
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    • 2008
  • This study was conducted to evaluate the sanitation level and use of dish cloths, chopping board, and drawer in the refrigerator in 50 university students' houses located in Seoul and Kyonggido. The survey questionnaire evaluated general information, frequency of the washing, cleaning method, drying method and the associated factors. The highest percentage of the cleaning and drying methods of dish cloths were “boiling(76.0%)”, and “dry in the kitchen or on the sink(78.0%)”, respectively. For the chopping board and drawer in the refrigerator, the highest percentage of cleaning method was “use detergent” and drying method was “dry in the kitchen”. The mean of coliforms for dish cloths, chopping board, and drawer in the refrigerator was 4.46${\pm}$1.95 log CFU/100 $cm^2$, 3.92${\pm}$1.64 log CFU/100 $cm^2$, 3.48${\pm}$2.01 log CFU/ 100 $cm^2$, respectively. Salmonella spp. were not detected from all samples. But E. coli were detected from dish cloths(4.0%) and S. aureus were detected from dish cloths(16.0%), chopping board(12.0%), and drawer in the refrigerator(8.0%). The results of microbiological test of kitchen utensils indicated that the sanitary conditions of dish cloths, chopping board, drawer in the refrigerator should be improve promptly.

METHODS TO IMPROVE UTILIZATION OF RICE STRAW I. EFFECTS OF MOISTENING, SODIUM CHLORIDE AND CHOPPING ON INTAKE AND DIGESTIBILITY

  • Badurdeen, A.L.;Ibrahim, M.N.M.;Schiere, J.B.
    • Asian-Australasian Journal of Animal Sciences
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    • v.7 no.2
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    • pp.159-164
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    • 1994
  • Two studies were conducted using 40 cross-bred bulls to study the effect of chopping, moistening with water or common salt solution on the nutritive value of rice straw (variety BG-400). Moistening with water did not significantly effect digestibility or intake of rice straw. As compared to straw fed in the long form, chopping did not significantly influence intake (2.33 vs 1.97kg $100kgBW^{-1}day^{-1}$, respectively), but significantly (p<0.05) decreased the digestibility (41.6 vs 37.4%) and intake of digestible dry matter (0.99 vs 0.74kg $100kgBW^{-1}day^{-1}$). Rice straw moistened with 2 or 4% common sea salt solution and directly fed to animals (Exp. 1) did not significantly effect its digestibility (43.9 and 43.1%, respectively) or intake (2.66 or 2.59kg $100kgBW^{-1}day^{-1}$, respectively), but over night storing of 2% salt solution sprayed straw (Exp. 2) significantly reduced its digestibility (33.6%). The latter is difficult to explain because the sodium concentration (mg/g straw dry matter) was lower than 4% salt solution treatment used in experiment 1 (3.30 vs 5.22). It is concluded that chopping, moistening with water or NaCl salt solution did not significantly improve the nutritive value of rice straw.

Chopper Application for Magnetic Stimulation

  • Choi, Sun-Seob;Lee, Sun-Min;Kim, Jun-Hyoung;Kim, Whi-Young
    • Journal of Magnetics
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    • v.15 no.4
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    • pp.213-220
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    • 2010
  • Since the hypothalamus immediately reacts to a nerve by processing all the information from the human body and the external stimulus being conducted, it performs a significant role in internal secretion; thus, a diverse and rapid stimulus pulse is required. By detecting Zero Detector accurately via the application of AVR on-Chip (ATMEL) using commercial electricity, chopping generates a stimulus pulse to the brain using an IGBT gate to designate a new magnetic stimulation following treatment and diagnosis. To simplify and generate a diverse range of stimuli for the brain, chopping can be used as a free magnetic stimulator. Then, commercial frequency (60Hz) is chopped precisely at the first level of the leakage transformer to deliver an appropriate stimulus pulse towards the hypothalamus when necessary. Discharge becomes stable, and the chopping frequency and duty-ratio provide variety after authorizing a high-pressure chopping voltage at the second level of the magnetic stimulator. These methods have several aims. The first is to apply a variable stimulus pulse via accurate switching frequency control by a voltaic pulse or a pulse repetition rate, according to the diagnostic purpose for a given hypothalamus. Consequently, the efficiency tends to increase. This experiment was conducted at a maximum of 210 W, a magnetic induced amplitude of 0.1~2.5 Tesla, a pulse duration of $200{\sim}350\;{\mu}s$, magnetic inducement of 5 Hz, stimulus frequency of 0.1~60 Hz, and a duration of stimulus train of 1~10 sec.

Antimicrobial Effect of Various Chopping Boards against Food-borne Bacteria (도마의 재질별 식중독 원인균에 대한 항균효과)

  • Kim, Ji-Young;Lee, Hyoung-Jae;Cho, Jeong-Yong;Lim, Hyun-Cheol;Choi, Gyeong-Cheol;Kim, Du-Woon;Park, Keun-Hyung;Moon, Jae-Hak
    • Korean Journal of Food Science and Technology
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    • v.44 no.1
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    • pp.114-120
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    • 2012
  • The purpose of this study was to evaluate the antibacterial activities of chopping boards made of various materials such as three antibiotic plastics, a general plastic, and various woods (red pine, rubber tree, cypress, birch, and bamboo) using zone inhibition assay and real-time PCR. Wood chopping boards showed high antimicrobial activity against Vibrio vulnificus, while plastic chopping boards showed high antimicrobial activity against Escherichia coli O157:H7, Salmonella Typhimurium, and Staphylococcus aureus. Bamboo chopping board among the wood chopping boards showed the highest antimicrobial activity against five foodborne bacteria such as E. coli O157:H7, S. Typhimurium, Vibrio cholerae, and V. vulnificus. These results may be helpful in the selection of a chopping board with high antimicrobial activity and in the application of hygiene procedures for prevention of cross-contamination.

Generalized techniques of harmonics elimination in thyristor AC chopper (싸이리스터 AC chopper의 고주파제법에 관한 연구)

  • 한송엽;원상철
    • 전기의세계
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    • v.24 no.6
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    • pp.92-96
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    • 1975
  • A generalized theroretical method is developed to eliminate a given number of harmonics in AC chopper output waves. The results show that halfwave symmetric and sinusoidal symmetric chopping are required to eliminate all even numbers of harmonics and , at least, M+1 times per half cycle chopping is required to eliminate any M odd number of harmonics in the given effective value of the output wave.

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Effect of Proprioceptive Neuromuscular Facilitation Chopping Pattern on Neglect, Balance, and Activity of Daily Living of Stroke Patients with Hemi-Spatial Neglect: A randomized clinical trial (고유수용성신경근촉진법 내려치기 패턴 훈련이 편측무시가 있는 뇌졸중 환자의 편측무시, 균형능력 및 일상생활수행능력에 미치는 영향: 무작위 임상 시험)

  • Kang, Tae-Woo;Kim, Beom-Ryong
    • Journal of the Korean Society of Physical Medicine
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    • v.14 no.2
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    • pp.107-115
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    • 2019
  • PURPOSE: This study examined the effects of the chopping pattern of proprioceptive neuromuscular facilitation (PNF) on the neglect, balance ability, and activities of daily living in stroke patients with hemi-spatial neglect. METHODS: Twenty stroke patients with neglect volunteered for this study. The subjects were assigned randomly to either the experimental group (EG, n=10) or control group (CG, n=10). The chopping pattern of PNF and exercise therapy were applied in the EG and CG, respectively, for four weeks. Neglect, balance, and activities of daily living were evaluated at the pre-and post-intervention. The assessment tools included a line-bisection test, balance test using Space balance 3D, and modified Barthel index. The pre-and post-intervention values were compared in each group using a paired t-test and the between-group differences were assessed using an independent t-test. Statistical significance was set to ${\alpha}=.05$ for all variables. RESULTS: Significant differences were observed between the EG and CG in terms of neglect, balance, and activities of daily living (p<.05). Both groups showed significant improvement in neglect, balance, and activities of daily living (p<.05). CONCLUSION: These results suggest that the chopping pattern of PNF is effective in improving the hemi-spatial neglect, balance, and activities of daily living in stroke patients with neglect.

A Vacuum Circuit Breaker Model for simulation of Transient Overvoltages Using the PSCAD/EMTDC (PSCAD/EMTDC를 이용한 과도전압 모의를 위한 진공차단기 모델 개발)

  • Lee, Wook-Hwa;Lee, J.H.;Lee, Jin;Choi, J.W.
    • Proceedings of the KIEE Conference
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    • pp.232-234
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    • 2002
  • A Vacuum Circuit Breaker Model for simulation of transient overvoltages was developed by using the PSCAD/EMTDC. The Model includes the power frequency chopping current. Breaker withstand voltage, and quenching capability of High frequency currents. To verify the abilities of the breaker model, the simulation on the Lindmayer's single-phase circuit was carried out. The results show that using the proposed model, the transient overvoltages, current chopping, and multiple reignitions of vacuum breaker are properly reproduced as real phenomena. In further study, virtual chopping current will be incorporated into the model for 3 phase system.

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Estimating the Effect of Overvoltage Results from Excitation Current Chopping in Short-circuit Transformer (여자전류 재단에 따른 단락 시험용 변압기의 절연영향 평가)

  • Oh, Seung-Ryle;Park, Ji-Hun;Park, Jong-Wha
    • Proceedings of the KIEE Conference
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    • pp.78-80
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    • 2007
  • The residual flux in transformer's iron cores leads to a distortion of short-circuit current occasionally. And some considerable distortion may have effect on the validation of the test results. To avoid the substantial distortion, a suitable pretest is performed before the actual test. In case of applying this method there must be excessive overvoltage due to switching of an unloaded transformer and chopping of an excitation current. The purpose of this paper is estimate that the effect of the overvoltage results from this phenomenon on insulation performance of short-circuit transformer.

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