• Title/Summary/Keyword: dB difference

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Olfactory Dysfunction in Chromium Exposed Workers (크롬 취급 근로자의 후각장애에 관한 조사연구)

  • Yu, Yeong-Jin;Ohm, Sang-Hwa;Lee, Jong-Tae;Yu, Byung-Chul;Jung, Kui-Oak;Cho, Kyu-Il;Pai, Ki-Tack
    • Journal of Preventive Medicine and Public Health
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    • v.28 no.3 s.51
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    • pp.678-689
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    • 1995
  • Chromium is one of the representative toxic substance by occupational exposure which damage the mucosa of respiratory tract including nasal septal perforation. The aim of this study is to evaluate the effect of chromium exposure on olfactory function and to obtain the fundamental information about chromium exposure. The authors performed olfactory function test, laboratory tests and questionnaire interview on the subject of three groups, that is, two exposed groups and one nonexposed group from May 1 to June 30, 1994. Exposed group 1 was 15 male workers without nasal septal perforation, exposed group 2 was 15 male workers with nasal septal perforation among 103 workers in 22 chromium plating factories, and nonexposed group was 15 male medical students. The gathered informations were histories of chromium exposure, habits of smoking and alcohol drinking, the concentrations of chromium in serum and urine, and asparate aminotransferase(AST), alanine aminotransferase(ALT), gamma-glutamyl transferase, etc. Olfactory function was checked by T and T olfectometer using phenyl ethyl alcohol(material A), methyl cyclopentenolone(material B), iso-valeric acid(material C), $\gamma$-undecalactone(material D), skatole(material E) and the results were expressed by detection threshold(DT) and recognition threshold(RT). There was a significant difference between exposed groups and nonexposed group in A, B, C, D, E substances by DT and in A, B, C, D substances by RT(P<0.01). The degree of olfactory dysfunction was highest in the exposed group 2 and lowest in the nonexposed group in all five substances by DT and it was same in A B, D substances RT and the difference of RT and DT. As summary, olfactory dysfunction by chromium exposure was recognized and the degree of olfactory dysfunction was higher in the exposed group with nasal septal perforation. Therefore, it would be helpful to apply olfactory function test for the early detection of olfactory dysfunction, and this test would be considered as the basic tool within workers' compensation system.

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A Fast Motion Vector Search in Integer Pixel Unit for Variable Blocks Siz (가변 크기 블록에서 정수단위 화소 움직임 벡터의 빠른 검색)

  • 이융기;이영렬
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.40 no.5
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    • pp.388-396
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    • 2003
  • In this paper, a fast motion search algorithm that performs motion search for variable blocks in integer pixel unit is proposed. The proposed method is based on the successive elimination algorithm (SEA) using sum norms to find the best estimate of motion vector and obtains the best estimate of the motion vectors of blocks, including 16${\times}$8, 8${\times}$16, and 8${\times}$8, by searching eight pixels around the best motion vector of 16${\times}$16 block obtained from all candidates. And the motion vectors of blocks, including 8${\times}$4, 4${\times}$8, and 4${\times}$4, is obtained by searching eight pixels around the best motion vector of 8${\times}$8 block. The proposed motion search is applied to the H.264 encoder that performs variable blocks motion estimation (ME). In terms of computational complexity, the proposed search algorithm for motion estimation (ME) calculates motion vectors in about 23.8 times speed compared with the spiral full search without early termination and 4.6 times speed compared with the motion estimation method using hierarchical sum of absolute difference (SAD) of 4${\times}$4 blocks, while it shows 0.1dB∼0.4dB peak signal-to-noise ratio (PSNR) drop in comparison to the spiral full search.

Effects of Organic Feed Supplementation on Feed Intake, Nutrient Digestibility, and Nitrogen Retention in Korean Native Goats(Capra hircus) (유기사료급여가 흑염소의 사료섭취량, 영양소소화율 및 질소 축적에 미치는 영향)

  • Jo, Ik-Hwan;Lee, Sung-Hoon
    • Korean Journal of Organic Agriculture
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    • v.13 no.1
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    • pp.85-99
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    • 2005
  • This trial was carried out to determine effects of organic feeds in comparison to conventional diet on feed intake, digestibility, and nitrogen retention in Korean native goats. Twelve Korean native goats were allotted to treatments in four groups of three goats and then they were housed in separate metabolism cages for 21 days. Treatments included conventional diet (A) as a control group and three organic feed groups (B: organic rice straw, C: organic nee leaves, D: organic mixture of rice straw and tree leaves). The A treatment, conventional diet, consisted of common rice straw and commercial concentrates at a proportion of 60 and 40%, respectively. All ingredients of organic feeds treatments were organically produced-agricultural products without any application of chemical fertilizer and pesticide. Four experimental diets were formulated to have the same ratio of forage to concentrate and similar contents for protein and carbohydrate across treatments and they were offered to goats ad libitum. Feed intake, apparent nutrient digestibility and nitrogen retention were investigated. For chemical compositions of experimental diets, all nutrients except crude ash and ether extract were not significantly different across treatments as we expected. Crude ash content was highest in the A treatment (P<0.05), however, it was not significantly different among organic feeds treatments. Ether extract content was higher (P<0.05) in C and D treatments than in A and B. Even if dry matter intakes for organic feeds treatments were not significantly different among them, they were significantly higher (P<0.05) compared with conventional diet. Fecal excreta were not significantly different across treatments, resulting in significantly higher digestible dry matter (g/day) in treatments of organic feeds (P<0.01). Average daily gain (ADG) and feed efficiency (FE) were more increased (P<0.01) in treatments of organic feeds compared with conventional diet. Digestibilities for most of nutrients except NFC had the same trend as ADG and FE, however, NFC digestibilities for C and D treatments were significantly lower (P<0.01) than those of A and B. Nitrogen intakes for organic feeds treatments were significantly higher (P<0.001) than conventional diet, with no difference among organic feeds treatments. Fecal nitrogen loss was higher (P<0.05) for C and D treatments than for A and B. Retained nitrogen contents were significantly higher (P<0.05) for organic feeds treatments than for conventional diet, but nitrogen retention rate did not show any difference across treatments. The results showed that organic feed supplementation more improved feed intake, digestibility and nitrogen retention in comparison with conventional diet, and thus they could be concluded that organic feeds might contribute to animal performance and a safer production of animal product.

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-1 Mode Circular Polarization Antenna Design by Using Cross Aperture-Coupled Feed (십자 개구 결합 급전을 이용한 -1 모드 원형 편파 안테나)

  • Kim, Jun-Sik;Lee, Jeong-Hae
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.25 no.2
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    • pp.156-163
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    • 2014
  • In this paper, a compact circularly polarized metamaterial patch antenna using cross aperture-coupled feed is proposed. The CP antenna utilizes the -1 mode that is induced by the composit right-left handed(CRLH) transmission line. Since the -1 mode has the same properties with the $TM_{010}$ mode of the conventional patch antenna, the circular polarization(CP) can be realized. If two orthogonal modes are excited with $90^{\circ}$ phase difference, the CP property can be obtained. In order to obtain two orthogonal modes and $90^{\circ}$ phase difference, 4 mushroom structures having the shape of square are employed. The width and length of the cross aperture are optimized through the design algorithm. The fabricated antenna is based on RT/duroid5880 substrate and the total area of the 4 mushroom is $0.25{\lambda}_0{\times}0.25{\lambda}_0$. The center frequency of the LHCP(Left-Handed Circular Polarization) antenna is measured as 1.622 GHz and circular polarization bandwidth(3 dB) is measured as 3 MHz. The center frequency of the RHCP(Right-Handed Circular Polarization) antenna is measured as 1.609 GHz and circular polarization bandwidth (3 dB) is measured as 3 MHz, respectively. The measured radiation efficiency of LHCP antenna is 61.1 % and the measured radiation efficiency of RHCP antenna is 54.5 %.

Evaluation of Usefulness of CT Angiography in the Lower Extremity using Heart Rate (심박동 수를 활용한 Lower Extremity CT Angiography 검사의 유용성 평가)

  • Sung-Sik, Kim;Ho-Sung, Park
    • Journal of the Korean Society of Radiology
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    • v.17 no.1
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    • pp.53-62
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    • 2023
  • The purpose of this study is to find an optimized imaging technique and evaluate its usefulness by comparing and analyzing the difference in contrast enhancement of lower extremity artery according to the patient's heart rate during lower extremity Computed Tomography Angiography examination. From January 2022 to August 22nd, 139 outpatients who visited Ajou University Hospital and underwent lower extremity angio CT examination were targeted. According to the heart rate, the groups were divided into four groups: A(HR ≤65), B(65 < HR < 80), C(80≤ HR). In addition, among patients with a heart rate of 65 or less, the heart rate was considered, and the scan was divided into D, E, F group with a delay time. The time of arrival of contrast medium and the average value of contrast enhancement were compared and analyzed. As a result of quantitative evaluation, B and C groups with a heart rate of more than 65 times had better HU values in the popliteal artery than A group (HR ≤ 65), and D group showed better HU improvement effects compared to A group (p<0.001). The comparative analysis with other groups was insignificant. The difference in heart rate affected the angiographic intensity of the lower extremities artery. Therefore, it is effective to apply the appropriate test timing for each patient by using the heart rate during the lower extremity angio CT Scan.

Application of PRA to The Differenec Image for Prediction Error Reduction in DPCM Image Coding (DPCM 영상 부호화기에서 예측 오차를 줄이기 위한 변환된 영상에서의 PRA 적용)

  • 문주희;고종석;김재균
    • Proceedings of the Korean Institute of Communication Sciences Conference
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    • 1986.10a
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    • pp.56-58
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    • 1986
  • This paper propose a conversion method to reduce prediction error produced when PRA(Pel Recursive Algorithm) motion estimation method is used in real image. The method is th get a spatial difference image from a given raw image and then to apply any PRA method to the difference image. The algorithm proposed in this paper is compared with several algorithm including the ubiquitious Netravali and Robbins` based on the performance and the hardware complexity. Computer simulation shows that the difference image conversion method is about 4.5dB better than the other algorithm with regard to prediction error power.

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A Difference-Blocked Current Differential Relaying Algorithm for Power Transformers (차전류 차분 방지 변압기 보호용 전류차동 계전방식)

  • Kang, Y.C.;Kim, D.S.;Kim, E.S.;Won, S.H.;Lee, B.E.
    • Proceedings of the KIEE Conference
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    • 2002.07a
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    • pp.16-18
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    • 2002
  • This paper proposes a difference-blocked current differential relaying algorithm for power transformers. The proposed algorithm observes that the shape of the differential current is changed using the difference. If the change is detected, output of current differential relay is blocked for a certain time. In this way, the algorithm distinguishes internal faults from magnetizing inrush. The proposed algorithm uses only currents and is unaffected by the remanent flux.

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Semi-lumped Balun Transformer using Coupled LC Resonators

  • Park, Jongcheol;Yoon, Minkyu;Park, Jae Yeong
    • Journal of Electrical Engineering and Technology
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    • v.10 no.3
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    • pp.1154-1161
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    • 2015
  • This paper presents a semi-lumped balun transformer using conventional PCB process and its design theory and geometry for the maximally flat response and wide bandwidth using magnetically coupled LC resonators. The proposed balun is comprised of two pairs of coupled resonators which share one among three LC resonators. It provides an identical magnitude and phase difference of 180° between two balanced ports with DC isolation and an impedance transformation characteristic. Theoretical design and analysis were performed to optimize the inductance and capacitance values of proposed balun device for obtaining the wide bandwidth and maximally flat response in its pass-band. Three balun transformers with a center frequency of 500 MHz were demonstrated for proving the concept of design proposed. They were fabricated by using lumped chip capacitors and planar inductors embedded into a conventional 4-layered PCB substrate. They exhibited a maximum magnitude difference of 0.8 dB and phase difference within 2.4 degrees.

A Current Differential Relaying Algorithm for Power Transformers Using the Difference of a Differential Current (차전류의 차분을 이용한 변압기 보호용 전류차동 계전방식)

  • Kang, Y.C.;Kim, D.S.;Lee, B.E.;Kim, E.S.;Won, S.H.
    • Proceedings of the KIEE Conference
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    • 2002.11b
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    • pp.274-276
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    • 2002
  • This paper proposes a current differential relaying algorithm for power transformers using the third difference function of a differential current. The algorithm observes the instants when the wave-shape of the differential current is changed due to the change of the magnetization inductance. If the value of the third difference is bigger than the threshold, the output of a current differential relay is blocked for a cycle. In the cases of magnetic inrush and overexcitation, the blocking signal is maintained: however, for internal faults, reset in a cycle. The test results clearly show that the algorithm successfully distinguishes internal faults from magnetizing inrush.

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Improved Channel Level Difference Quantization for Spatial Audio Coding

  • Kim, Kwang-Ki;Beack, Seung-Kwon;Seo, Jeong-Il;Jang, Dae-Young;Hahn, Min-Soo
    • ETRI Journal
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    • v.29 no.1
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    • pp.99-102
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    • 2007
  • The channel level difference (CLD) is a main parameter in the reference model 0 (RM0) for MPEG Surround. Nevertheless, the CLD quantization method in the RM0 has problems such as the lack of theoretical background and inappropriate quantization levels. In this letter, a new CLD quantization method is proposed based on the virtual source location information which has strength in the quantization process. From experimental results, it is confirmed that the proposed scheme greatly reduces the quantization distortions measured in dB and degrees without any additional complexity.

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