IIR 적응필터를 이용한 오차보상 능동소음제어

권기룡,박남천 慶南大學校 附設 工業技術硏究所 1993 硏究論文集 Vol.11 No.-

본 논문에서는 능동소음제어를 위하여 오차보상 RNLMS(recursive normalize least mean square)알고리듬(CRNLMS)을 제안하였다. 이 CRNLMS(error compensated RNLMS)알고리듬에서는 수렴속도를 빠르게 하기 위하여 입력소음과 오차소음의 전력에 따라 가변수렴인자를 사용하였다. 또한, 정상상태오차를 최소화하기 위하여 오차경로에서 소음발생기를 사용하지 않고 소음오차를 더욱 작아지도록 보상하는 보조시스템을 사용하였다. 시스템의 성능을 입증하기 위하여 기존의 적응디지틀필터인 RLMS(recursive LMS) 및 RNLMS알고리듬과 비교하였다. 컴퓨터 시뮬레이션 결과, 제안한 CRNLMS 알고리듬의 소음레벨은 RLMS 및 RNLMS알고리듬의 것보다 평균 12㏈ 및 3㏈ 정도 더 큰 감쇄효과가 있음을 확인하였다. In this paper, an error compensated RNLMS algorithm(CRNLMS) is proposed for an active noise control. This CRNLMS algorithm use the variable convergence factor according to the input and error noise power to fast convergence speed. And it uses an error compensated auxiliary system, which reduces error noise without random noise generator in error path, to minimize steady state error. To demonstrate the performance of the system, the p개posed CRNLMS algorithm is compared with the conventional ones, the RLMS and the RNLMS algorithms. The computer simulation results for each algirithm show that the noise level of the proposed CRNLMS algorithm is reduced about 12㏈ and 3㏈ as compared with the RLMS and RNLMS algorithms, respectively.

수영-스트레스에 의한 腦 Catecholamine 代謝의 變動에 있어서 甲狀腺-機能의 役割에 關한 硏究

洪起男,申炅浩,金炯健,全普權 고려대학교 의과대학 1989 고려대 의대 잡지 Vol.26 No.3

Effects of hyper-and hypothyroidism in the swim-stress(SS) induced changes of plasma corticosterone(CS) level and brain norepinephrine(NE) metabolism were studied in male mice pretreated with 1-thyroxine sodium(4㎎/㎏, i.p. inj. once a day for 5 days; T₄) and propylthiouracil (fed ad lib in 0.01% drinking water for 5 weeks : PTU). The circadian rhythm of spotaneous motor activity was not significantly altered by T₄ and PTU, respectively. The plasma thyroxine level was markedly increased by T₄ but reduced by PTU and the plasma thyrotropin level was markedly increased by PTU but decreased by T₄. The plasma CS level was not changed by PTU but moderately increased by T₄ Clonidine slightly increased the plasma CS level, but the clonidine effect was significantly enhanced by T₄-pretreatment. The brain NE and 3-methoxy-4-hydroxyphenylglycol(MHPG) contents were little affected by T₄ but significantly decreased by PTU. ThE SS-induced increase of plasma CS level was moderately decreased by PTU but increased by T₄. However, clonidine significantly inhibited the SS-induced increase, and the inhibitory effect of clonidine was little significantly affected by PTU and T₄ respectively. The brain MHPG content and MHPG/NE ratio were significantly decreased by clonidine bur increased by SS. THe clonidine-induced decrease of brain MHPG/NE ratio were not altered by PYTU or T₄. The SS-induced, and the inhibitory effect of clonidine was not affected by PTU and T₄ respectively. These results suggest 1) that the alteration of thyroidal function little affects the changes of brain NE in responses to swim-stress, but the stress-induced change of plasma corticosterone level may be somewhat modulated by the thyroidal function, and 2) that the hypothalamo-pituitary-adrenocortical stimulation in response to swim-stress seems to be mediated via hypothalamic noradrenergic activation, and the stress response may inhibited by the agonistic activity of clonidine on the presynaptic α₂-adrenoceptor.

경험적 정보를 이용한 kNN 기반 한국어 문서 분류기의 개선

임희석,남기춘 한국컴퓨터교육학회 2002 컴퓨터교육학회 논문지 Vol.5 No.3

문서 자동 분류란 입력 문서에 이미 정해져 있는 특정 범주를 할당하는 작업을 의미하며 이는 문서의 효율적, 체계적 관리를 위하여 그 필요성이 증가하고 있는 실정이다. 현재 국내외에서 기계 학습 방법을 이용한 문서 자동 분류에 대한 연구가 활발히 진행되고 있으나 대부분의 연구는 문서 분류기의 성능 향상을 위한 새로운 학습 모델 제안과 학습 모델간의 상호 비교 연구에 치중되어 있으며 특정 학습 모델을 이용한 분류 시스템의 최적화나 개선 방안에 대한 연구는 다소 미흡한 실정이다. 이에 본 논문은 kNN 학습 방법을 이용한 문서 분류 시스템의 성능 향상에 중요한 역할을 하는 파라미터를 정의하고 실험을 통해서 얻은 경험적 정보를 이용한 한국어 문서 분류기 성능 개선 방안을 제안한다. 실험 결과, 이웃 문서들간의 유사도 가중치를 사용하는 분류 함수, 분류 정보를 이용한 자질 선택 방법, 그리고 전역적 분류 방법이 높은 성능을 보였고, 분류 영역에 따라 신중히 결정된 k값을 사용한 지역적 방법도 많은 계산량을 필요로 하는 전역적 방법과 유사한 성능을 보일 수 있음을 확인하였다. Automatic text classification is a task of assigning predefined categories to free text documents. Its importance is increased to organize and manage a huge amount of text data. There have been some researches on automatic text classification based on machine learning techniques. While most of them was focused on proposal of a new machine learning methods and cross evaluation between other systems, a through evaluation or optimization of a method has been rarely been done. In this paper, we propose an improving method of kNN-based Korean text classification system using heuristic informations about decision function, the number of nearest neighbor, and feature selection method. Experimental results showed that the system with similarity-weighted decision function, global method in considering neighbors, and DF/ICF feature selection was more accurate than simple kNN-based classifier. Also, we found out that the performance of the local method with well chosen k value was as high as that of the global method with much computational costs.

光陸 및 五臺山의 主要森林 植物의 Energy 및 양분순환에 對하여

朴奉奎,金遵敏,張楠基 梨花女子大學校 韓國生活科學硏究院 1970 韓國生活科學硏究院 論叢 Vol.4 No.-

1. 森林植物의 地上部의 養分量은 葉枝, 幹中, 葉量과 그 含有比에 따라 決定된다. 2. N, P, K, Ca, Mg의 器管別 含有率은 잎이 가장 높고 가지가 中間이며 줄기가 제일 낮다. 3. 林木에 있어서는 落葉針葉樹가 N, P, K의 含有比가 가장 높았고 상록침엽수보다는 활엽낙엽수가 그含有比가 높았다. 4. 전나무, 잣나무, 참나무林에서는 養分現存量이 가장 높았고 소나무림이 가장 적었으며 서나무, 아카시나무, 낙엽송림은 中間程度였다. 5. 林牀에서 energy와 CO_2의 放出率의 大小는 서나무, 아카시나무, 참나무, 낙엽송, 잣나무, 전나무, 소나무落葉의 순서였다. 6. Energy와 有權炭素의 林牀堆積量의 多少는 放出量과 正反對 순위며 分解量은 同一한 순서였다. 7. 낙엽에 축척되어 있는 Energy가 半減하는데 要하는 時間은 서나무, 아카시나무, 참나무, 낙엽송, 잣나무, 소나무에 있어서 各各 1.8年, 2.0年, 2.6年, 2.7年, 36年, 4.5年, 5.3年이였다. 8. 토양으로 되돌아 가는 N, P, K, Ca의 無機養料의 量은 상록침엽수보다 낙엽활엽수림에서 더욱 많다. 9. 토양으로 되돌아 가는 Mg의 量은 樹種에 따라 다르며 소나무와 참나무林이 가장 많았고 서나무와 낙엽송림이 가장 적었다. 10. 森林에 있어서 降水에 依한 養分의 樹冠洗脫量은 K가 가장 많았고 Ca와 Mg은 中間이며 N과 P는 比較的 적었다. An inv estigation was performed to elwidate the energy flow and the nutruent cycle trees in Mt. Otae and Kwang-nung plantation stands. As the trees become larger, they contain greater amounts of natrients, and there were close relationships between the dry weights and the nutrient contents for each element habitat regionless of tree species and habitat conditions. A great portion of the nutrients in a tree is accumulated in the leaves. There was a tendency for the N,P,K and Ca concentration to be higher in deciduous forest tress, than in the evergreen coniferous forest trees. The decomposition rate of deciduous litters was than that of coniferous litters. The time required for the decomposition of half of the accumulated organic matter of deciduous litter and coniferous litter in the forest stands are 1.8∼2.6 years and 2.7∼5.7 years reapectively. The amounts of N,P,K and Ca returned annually to the soil is higher in the decidu ous forests than in the evergreen coniferous stands. Very large amounts of K, significant amounts of Ca and Mg, but only small amounts of N and P were leached from the canopy by rain. The amounts of nutrients in the litter fall and in the rain wash, together with anestimate of the amounts in the twig and timber fall, have been added together to give the rate of the nutrient cycle under these forests.

CT 보험급여 전후의 CT 및 MRI검사의 이용량과 수익성 변화

서종록,유승흠,전기홍,남정모 한국병원경영학회 1997 병원경영학회지 Vol.2 No.1

In order to analyze the shifts in the volume and profits of Computed Tomography(CT) and Magnetic Resonance Imagine(MRI) utilization for a year before and after the implementation of insurance coverage for CT, this study has been undertaken examining CT and MRI cost data from 'Y' University Hospital situated in Seoul, Korea. Following are the results of this study : 1. The medical insurance payment for CT, implemented on January 1, 1996, increased CT utilization from January 1996 to April 1996 due to low insurance premiums : however, from May 1996 the number of CT cases significantly decreased as a result of strengthened medical cost reviews and the new 'Detailed standards for approval of CT' announced near the end of April 1996 by the insurer. 2. Since the implementation of insurance coverage for CT, CT fee reduction rates for reimbursements by the insurer to the hospital were 50% and 40% for January and February, respectively, and 31% and 15% for March and April. A significant point in the lowering of the reduction rate was reached in May at 11% : furthermore, since June the reduction rate fell below the average reduction rate for reimbursements for all procedures. If the 'Detailed standards for approval of CT' had been announced before the implementation of insurance coverage for CT, CT utilization would not have been so high due to the need to meet those 'standards'. In addition, loss of hospital profits resulting from the reduction for reimbursements would not have occurred. 3. The shifts in MRI utilization showed that there was no particular change with the beginning of insurance coverage for CT, and the introduction of the 'Detailed standards for approval of CT' made MRI utilization increase because MRI is free of restrictions imposed by the insurer. 4. The relationship between CT utilization and MRI utilization shoed that they were supplementary to each other before insurance coverage for CT, but that CT was substituted for MRI because of strengthened medical cost reviews after the beginning of insurance coverage for CT. 5. The shifts in volume by patient characteristics showed that the number of inappropriate case patients, according to the insurer's "Standards for approval", decreased more than the number of appropriate case patients after the introduction of insurance coverage for CT. Therefore, the health insurance fee schemes for CT have influenced patient care. 6. The shifts in profits from CT utilization showed a net profit decrease of 31.6%. In order to match the pre-coverage profit level, 5,471 more cases would need to be seen and productivity would need to be increased by 32.7%. This profit decrease resulted from a decrease of CT utilization and low reimbursements. With insurance coverage, net profits from CT were 24.4%, and a margin of safety ratio was 39.6%. Because of the net profits and margin of safety ratio, CT utilization fees for insured appropriate cases could not be considered inappropriate. 7. The shifts in profits from MRI utilization before and after the introduction of CT coverage showed that in order to match pre-CT coverage profit levels, 2,011 more cases would need to be seen and productivity would need to be increased by 9.2%. The reasons for needing to increase the number of cases and productivity result from cost burdens created by adding new MRI units. But with CT coverage already begun, MRI utilization increased. Combined with a minor increase in the MRI fee schedule, MRI utilization showed a net profit increase of 18.5%. Net profits of 62.8% and a 'margin of safety ratio' of 43.1% for MRI utilization showed that the hospital relied on this non-covered procedure for profits. 8. The shifts in profits from CT and MRI utilization showed the net profits from CT decreased by 2.33 billion Won while the net profits from MRI increased by 815.7 million Won. Overall, these two together showed a net profit decrease of 1.51 billion Won. The shifts in utilization showed a functional substitution relationship, but the shifts in profits did not show a substitutionary relationship. From these results, We can conclude that if insurance is to be expanded to include previously uncovered procedures using expensive medical equipment, detailed standards should be prepared in advance. The decrease in profits from the shifts in coverage and changes in fees is a difficult burden that should be shared, not carried by the hospital alone. Also, a new or improved fee schedule system should include revised standards between items listed and the appropriateness of the fee schedule should constantly be ensured. This study focused on one university hospital in Seoul and is therefore limited in general applicability. But it is valuable for considering current issues and problems, such as the influence of CT coverage on hospital management. Future studies will hopefully expand the scope of the issues considered here.

우리나라 화학물질 관련 사고 대비 및 대응체계 분석

이종화,장봉기,박종안,김은화,김춘득,여은영,남상훈 순천향대학교 기초과학연구소 2004 순천향자연과학연구 논문집 Vol.10 No.2

Recently, several large chemical accidents took place in many countries. Therefore, many countries strengthened the regulation related to management of chemical safety. In case of our country, about 500 chemical accidents took place for the past decay. The preparation and response system for chemical accidents is a most important element for management of chemical safety. In this study, we analyze the preparation and response system for chemical accidents described in several regulations of our country, and suggest a more appropriate management system for chemical safety. Accident report documents vary among the Toxic Chemical Control Law, the Fire Services Law and the Industrial Safety and Health Law. In case of the Fire Services Law, there is not a concrete description about the source chemical of accident. The response authority for chemical accident is dualistic. Minister of Government Administration and Home Affairs is responsible for emergent rescue, on the other hand, ministers of central administrative branches are in charge of reconstruction of chemical accident. Therefore these dualistic system make confuse in response to a large chemical accident.

누두흉 환자에서 Nuss 금속막대 제거 전 · 후 폐 역학 변화

강규식,백남순,김천숙,안기량,권진형,김지은,유시현 순천향의학연구소 2003 Journal of Soonchunhyang Medical Science Vol.9 No.1

Nuss operation is one of the surgical procedure for pectus excavatum and it's method is the insertion of convex steel bar under the sternum through small bilateral thoracic incision. As the patients is growing, the thorax can be compressed gradually by steel bar. So Nuss bar needs to be removed two years after Nuss operation. This study was undertaken to assess the effect on the repiratory mechanics before and after the removal of the Nuss bar. Twenty patients with previous Nuss operation were allocated for the removal of Nuss bar. Lung mechanics (dynamic lung compliance, static lung compliance, and airway resistance), hemodynamic change (heart rate, systolic pressure, and diastolic pressure), and pulmonary gas exchange (arterial oxygen tension, arterial carbon dioxide tension, pulse oximeter saturation, and end tidal carbon dioxide tension) were measured before and after removal of Nuss bar. Respiratory mechanics (dynamic and static lung compliance, inspiratory airway resistance), pulmonary gas exchange and hemodynamic parameter were unchanged before and after the removal of Nuss bar. We concluded that lung mechanics were not changed before and after the removal of Nuss bar in the patients with pectus excavatum and the 95% patients were satisfied with operation.

廢CRT의 再活用 工程에서 발생한 슬러지로부터 Y의 회수

田埈美,李在天,鄭鎭己,金南澈 공주대학교 자원재활용 신소재 연구센터 2002 센터사업 성과집 Vol.- No.1

폐CRT의 재활용 공정에서 Panel 유리에 도포 된 형광체의 제거 시 발생하는 슬러지로부터 Y를 회수하는 연구를 수행하였다. HCl 및 NHO_3을 사용하여 Y를 침출하였으며 산 농도, 침출온도, 침출시간, 광액농도가 침출율에 미치는 영향을 조사하였다. 또한 침출액으로부터 Y와 Pb를 침전 법으로 회수하는 실험을 행하였다. 슬러지로부터 HCl 및 HNO_3에 의한 Y의 침출거동은 유사한 경향을 나타내었다. 광액농도를 280 g/L로 하여 90℃에서 3.0M HCl 및 HNO_3으로 침출 하였을 때 시간에 따라 Y의 침출율은 증가하다가 40분 이상에서는 각각 93%, 90%로 일정한 침출율을 나타내었다. 침출액에 H_2C_2O_4을 첨가하여 Y를 회수하였으며 Pb는 Na_2SO_4를 가하여 PbSO_4로 제거하였다. A study on the recovery of yttrium was conducted using the phosphor sludges generated in the recycling process of obsolete CRTs. Yttrium was leached by HCl and HNO_2. The leaching efficiency of yttrium was extensively investigated in terms of acid concentration, leaching temperature and time, and pulp density. Yttrium and lead was recovered from leaching solutions also by precipitation method. The leaching behavior of yttrium was similar in both acids. The leaching efficiency of yttrium for both acids increased with time at the conditions of 3.0M, 90℃, and 280 g/L of pulp density. After 40 minutes, it was saturated to 93% and 90% for HCl and HNO_3, respectively. Yttrium was recovered from leaching acid solution by the addition of H_2C_2O_4 while lead was removed as PbSO_4 by Na_2SO_4.

우리나라 화학물질 분류 및 표시체계 분석

박종안,장봉기,이종화,김은화,김춘득,여은영,남상훈 순천향대학교 기초과학연구소 2004 순천향자연과학연구 논문집 Vol.10 No.2

Classification and Labelling system of Chemicals is a very important element for management of chemical safety. Classification and labelling system of Chemicals is very different among countries. This becomes a barrier for transportation of chemicals across counties. Recently, several international organizations (OECD,UNEP,ILO etc.) endeavor to harmonize classification and labelling of chemicals. In this study, we analyze classification and labelling system of chemical described in several regulations of our country, and examine acivities of IOMC(Inter-Organization Programme for the Sound Management of Chemicals)for harmonization of classification and labelling of chemicals. The Toxic Chemical Control Law, the Fire Services Law and the Industrial Safety and Health Law are the major regulation of management of chemical safety. Classification and labelling systems of chemical vary among several regulations. Particularly, labelling system of chemicals in transport vehicles are not appropriate in response to chemical accident. We suggest that task force team consisted with inter-administrative branches is needed to harmonize classification and labelling of chemicals, and recommend the introduction of UN number in labelling systems of chemicals in transport vehicles.

실내 기후동에서 개인형 국소냉방 장치의 기류 및 온도 분포해석

엄태인,장은숙,경남호,신기식,문승현,전영남,류창국 한밭대학교 생산기반기술연구소 2002 생산기반기술연구소 논문집 Vol.2 No.1

Numerical simulation is performed by the commercial code FLUENT for individual air condition system to calculate the velocity and temperature profiles around worker in climate room. The main calculation region is the space of ㄱ shape between wall and worker in the individual air condition system. The fresh air is emitted from 3 inlet attached on the right, left and center wall. Because the comfort of worker is closely related with the velocity and temperature of wind, these data are key role for design of the individual air condition system. This work is previous study for evaluation of thermal comfort of workers in room without much experiments according to metabolism and heat emission of human body. Numerical simulation results are as followings, 1. There is an possibility of the thermal comfort of worker is gotten worse due to the presence of dramatic change of wind velocity around worker. 2. Temperature gap exists in worker's body between top and bottom according to fresh air inlet velocity and position which is right, left and center of wall. 3. Calculation results of the skin temperature of worker are key data for evaluation of thermal comfort with experimental data in climate room. 4. Optimum condition of temperature, direction and velocity of fresh air will be obtain by numerical simulation for energy effective individual air condition system.