• 제목/요약/키워드: Non-uniform

검색결과 2,188건 처리시간 0.029초

$^{18}F$-FDG PET 영상의 정량적 비교: PET/MR VS PET/CT (Quantitative Comparisons in $^{18}F$-FDG PET Images: PET/MR VS PET/CT)

  • 이무석;임영현;김재환;최규오
    • 핵의학기술
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    • 제16권2호
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    • pp.68-80
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    • 2012
  • 감쇠 보정법과 산란 보정법은 정량적인 PET검사를 하기 위한 필수적인 방법이다. PET/CT에서는 PET에서 사용하는 소멸방사선과 CT의 X선이 같은 전리 방사선이기 때문에 측정에 의한 CT의 Hounsfield Units를 감쇠 계수로 전환해서 감쇠보정, 산란보정이 가능하다. 그러나 PET/MR에서 MR는 강한 자기장을 걸어 수소밀도와 조직의 이완률차이로 되돌아오는 변화로 신호를 획득하기 때문에 CT처럼 전환하는 것은 불가능하다. Ingenuity TF PET/MR장비는 soft tissue, lung, air로 3구역을 segment하여 MR 감쇠지도를 얻는다. 이에 신호획득원리가 완전히 상이한 PET/MR과 PET/CT에 대한 정량적 평가를 하고자 한다. Phantom study로 uniform cylinder phantom에 증류수 9293 ml와 $^{18}F$-FDG 199.8 MBq를 넣고 magnetic stirrer를 이용하여 균일하게 교반한 후 60 min부터 15분 간격으로 Ingenuity TF PET/MR, Gemini TF 64, Biograph Truepoint 40를 이용하여 각각 single-bed로 2 min씩으로 영상을 얻었다. phantom의 중심부분 10개의 slice에 대한 동일한 관심영역을 그려 SUVs를 측정하고 평균, 표준편차를 구하였다. 그리고 임상적용을 위한 평가로 $^{18}F$-FDG 섭취가 정상인 환자를 대상으로 90 sec/bed씩 Ingenuity TF PET/MR을 시행한 후 Gemini TF 64 PET/CT 검사를 실시하였다. 각각의 data에서 lung, liver, spleen, bone 위치에 동일한 관심영역을 그려 SUVs 최대값과 평균값을 측정하고, %Difference를 구하였다. 또한, PET 장비들 사이에서의 일치도를 평가하기 위해 Bland-Altman plot 분석을 하였다. Phantom study에서 3가지 장비에서 측정한 SUVs 최대값과 평균값은 Biograph Truepoint 40, Gemini TF 64, Ingenuity TF PET/MR 순으로 높은 것을 확인할 수 있었다. patients study에서는 MR과 CT로 감쇠 보정한 PET장비의 SUVs 최대값과 평균값이 서로 유의미한 차이가 없었다.(p<0.05) Lung에서 left middle lobe과 transverse bone을 제외하고는 MR로 감쇠 보정한 PET의 SUVs가 대체로 낮았다. Bland Altman Plot으로 분석한 결과 대부분의 항목에서 95% 신뢰구간의 일치한계선내에서 측정되었다. PET/CT에서는 time of flight 기능을 가진 PET이 SUVs가 낮게 측정되었다. PET/MR과 PET/CT에서 알아본 SUVs차이는 MR을 이용한 분할 감쇠 보정방법이 CT를 사용한 측정 감쇠보정방법보다 SUVs가 낮게 측정되었다. 이러한 다른 감쇠 보정법에 의한 SUVs의 차이는 임상적으로는 용인할 수준에 있었지만, 향후 PET/MR와 PET/CT의 정량적인 값을 비교 분석할 때 PET 장비들간의 특성은 고려할 필요가 있다.

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한국장신구의 사치 금제 고찰 (A Study on Luxury Prohibition of Korean Personal Ornaments)

  • 추원교
    • 디자인학연구
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    • 제2권1호
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    • pp.43-62
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    • 1989
  • The luxury is the expression of human being's ornament instinct. In this study, in order to grasp the moulding system of the Korean's personal ornaments, the process of luxury prohibition was reviewed to search for to which direction the ornaments developed in the frame of the prohibited style connected closely to the character of the personal ornaments. The proiod was fixed from the old society to the late Chosun dynasty era. The beginning of the luxury in Korea seems to be the start of the luxury burial at the time of funeral in the age of Koguryo., In the era of Koguryo, 10th year of King Dongmyung (B. C. 28), in the era of Baekje, 27th year of King Koi(260), the prohibition of dress regulation and the style of dress were conducted. The prohibition of personal ornaments in Silla was started from King Bup:Heung, and in the 9th year of King Heung-Duk, the prohibition was conducted in order to correct the luxury of the nobles and set up the social discipline. In the 11 th of King Il-Sung-Ni-Sa-Kum, the use of gold, silver and jade was prohibited in the civilian circles. The prohibition of Silla was succeeded to Koryo era, and in the 7th year of King Kwangjong(956), the system of Baekgwan Gongbok(uniform for government officials) was set up, and the system of Sasek Gongbok(four color official uniform) was set up in the 11 th year of the same King, and the prohibition of the personal ornaments such as crown and band is considred to have been conducted. The prohibition of gold and silver was conducted in the first year of King Sungjong(982), and in the 4th year of King Chungryul(l260), the order of wearing the dress and hat in accordance with the Yusan dynasty and the Mongolian customs were widely circulated in the royal court and vivilian circles. The strong influence of Mongolia made the taste of the traditional personal ornaments laste. The personal ornaments were used for the nobles until the age of the Unified Sillar but even the common people could use them in case they were rich, and such a circumstances made the use of foreign goods inflated. The prohibition of Koryo era was aimed at the prohibition of the foreign goods of luxury, and the classification of the social status.In the age of Chosun Dynasty, the production of gold and silver was feeble indeed but the oute reason of the prohibition was to eradicate the luxurious tendency, elevate the custom of eradicate the luxurious tendency, elevate the custom of thrift, and moreover, the gold, silver and jade were no the products of Korea and the prohibition was conducted but the true reason was afor the tribute tt China and the classification of status. The prohibition of Chosun dynasty was conducted first in the June of the 3rd year of King Taejo The major contents of prohibition was no use of gold, silver and jade, coral, agate, amber, etc. of th, wives of the Dang-Sang-Kwan (Court Nobleman) or their sons and daughters, and the same pheno menon was common even at the time of marriage. The people engaged in the secret trade there of wert beheaded. The personal ornaments in the prohibition were the pendent trinket, Binyo (crossbar) ceremonial ornamental hat, ring, earring, ornamental knife, hat string, hat ornament, belt, etc. Thl luxurious marriage expenses out of the luxury was severe, and lose of the marriageable age because 0 non-preparing the marriage goods was the national evil. The prohibition oC luxury was hard to bt kept to the nobles or rich people, the same as old days and present days. The prohibition of th{ luxury and personal ornaments of Korea had nothing to do with the commons, and it was limited tc the nobles and rich people. The prohibition was aimed to cultivating the custom of frugality by eradicating the luxurious atmosphere, but it was chiefly due to the tribute to the China and tht discrimination of the. status. We can say that the recent personal ornament was the flower of handi craft industry bloomed in the prohibition and regulation.

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다중 섬광결정을 이용한 고해상도 PET의 불균일/불완전 데이터 보정기법 연구 (Compensation Methods for Non-uniform and Incomplete Data Sampling in High Resolution PET with Multiple Scintillation Crystal Layers)

  • 이재성;김수미;이건송;심광숙;이준택;박광석;이동수;홍성종
    • Nuclear Medicine and Molecular Imaging
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    • 제42권1호
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    • pp.52-60
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    • 2008
  • 목적: 다중섬광결정 PET으로 얻은 데이터에 대한 여과후역투사 영상재구성 적용을 위한 사이노그램 저장과 보정 방법을 확립하고자 한다. 대상 및 방법: 검출된 PET 데이터에 대한 저장기법에 대한 연구를 수행하여 효율적 영상재구성을 위한 사이노그램 방식을 확립하였다. 히스토그램에서 사이노그램으로 데이터를 변환할 때 생기는 제반 문제들을 해결하기 위하여 데이터 표본의 최적화와 표본 불균일성 보정기법에 관한 연구를 수행하였으며, PMT간 틈새 보정을 위 한 연구를 수행하였다. 모든 데이터는 2차원 여과후역투사 알고리즘을 이용하여 재구성하였으며 보정에 따른 영상질의 향상을 평가하였다. 결과: 표본이론에 의해서 추정된 최소 표본수와 표본 불균일성 보정기법의 적용을 위한 수월성 등을 고려할 때 방사방향 표본간격이 pitch/2, 각 표본수가 120개 정도가 적절하였으며, 불균일성 보정과 틈새보정을 적용함으로서 영상왜곡과 배경잡음을 줄일 수 있었다. 결론: 다층섬광결정 PET의 FBP 영상재구성을 위하여 히스토그램 데이터를 사이노그램으로 변환하는 기법에 대한 연구가 이루어졌으며 이를 통한 고속의 2D 영상재구성이 가능할 것으로 보인다.

Evaluation of different milking practices for optimum production performance in Sahiwal cows

  • Aslam, Naveed;Abdullah, Muhammad;Fiaz, Muhammad;Bhatti, Jalees Ahmad;Iqbal, Zeeshan Muhammad;Bangulzai, Nasrullah;Choi, Chang Weon;Jo, Ik Hwan
    • Journal of Animal Science and Technology
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    • 제56권4호
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    • pp.13.1-13.5
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    • 2014
  • The production performance of multiparous lactating Sahiwal cows (n = 24) was evaluated according to both milking frequency and method. Selected animals were randomly divided into four groups containing six animals each under a completely randomized design. Cows in groups A & B were milked by the hand milking method three times per day, respectively. Similarly, cows in groups C & D were milked by the machine milking method two and three times per day, respectively. All animals were maintained under uniform feeding and management conditions. Dry matter intake was high in animal groups milked three times per day, and it remained unchanged between the hand and machine milking methods. Milk yield was higher (P < 0.05) in cows milked three times compared to those milked twice per day, and it did not differ between hand and machine milking methods. Milk fat percentage was higher (P < 0.05) in cows milked twice per day compared to those milked three times using both machine and hand milking methods. The percentage of total solids showed a similar pattern as the fat percentage. However, percentages of protein, lactose, and non-fat solids in milk were not significantly different (P > 0.05) among the treatment groups. Collectively, the results show that milking three times per day instead of twice at 8-hour intervals can enhance milk yield in Sahiwal cows using both hand and machine milking methods.

Response of Millet and Sorghum to Water Stress in Converted Poorly Drained Paddy Soil

  • Jung, Ki-Yuol;Yun, Eul-Soo;Park, Chang-Young;Hwang, Jae-Bok;Choi, Young-Dae;Oh, In-Seok
    • 한국토양비료학회지
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    • 제46권6호
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    • pp.409-416
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    • 2013
  • Millet and sorghum are major dryland cereal crops, however their growth and productivity is limited by soil water stress with varying intensity. The major objective of this study was to evaluate water stress of millet and sorghum yield under drainage classes of poorly drained soil and to test the effect of the installed pipe drainage in poorly drained paddy soil to minimize crop stress. The research was carried out in poorly drained paddy fields located at alluvial slopping area resulting in non-uniform water content distribution by the inflow of ground water from the upper part of the field. Stress Day Index (SDI) was determined from a stress day factor (SD) and a crop susceptibility factor (CS). SD is a degree of measurement by calculating the daily sum of excess water in the profile above 30cm soil depth ($SEW_{30}$). CS depends on a given excess water on crop stage. The results showed that sum of excess water day ($SWD_{30}$) used to represent the moisture stress index was lower on somewhat poorly drained soil compared with poorly drained soil on 117 days. CS values for sorghum were 57% on $3^{rd}$ leaf stage, 44% on $5^{th}$ leaf stage, 37% on panicle initiation, 23% on boot stage, and 16% on soft dough stage. For proso millet CS values were 84% on $3^{rd}$ leaf stage, 70% on $5^{th}$ leaf Stage, 65% on panicle initiation, 53% on boot stage, and 28% on soft dough stage. And for foxtail millet the values were 73% on $3^{rd}$ leaf stage, 61% on $5^{th}$ leaf stage, 50% on panicle initiation, 29% on boot stage, and 15% on soft dough stage. SDI of sorghum and millet was more susceptible to excess soil water during panicle initation stage more poorly drained soil than somewhat poorly drained soil. Grain yield was reduced especially in proso millet and Foxtail millet compared to Sorghum.

가시설 부식 강재의 잔존 인장 내하성능 평가에 관한 실험적 연구 (An Experimental Study on the Evaluation of Residual Tensile Load-carrying Capacity of Corroded Steel Plates of Temporary Structure)

  • 김인태;장홍주;정지영
    • 한국강구조학회 논문집
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    • 제22권5호
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    • pp.399-409
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    • 2010
  • 강구조물은 부식에 의한 단면감소와 이로 인한 내하성능의 저하가 우려된다. 그러나 부식손상이 강부재의 내하성능에 미치는 영향과 잔존 내하성능 평가법은 명확하게 정립되어 있지 않은 실정이다. 본 연구에서는 부식 손상된 지하철 가시설 주형보의 웨브와 플랜지에서 절취한 부식시편의 인장실험을 실시하여, 부식손상이 인장 내하성능에 미치는 영향과 인장 잔존 내하성능 평가법에 대하여 검토하였다. 부식 가시설 주형보로부터 절취한 총 21개의 부식시편은 먼저 화학적 방법에 의해 부식생성물을 제거하고 1mm간격으로 표면형상을 측정한 후 인장실험을 실시하였다. 이러한 인장실험 결과는 주형보의 플랜지에서 절취하여 두께 13mm로 기계 가공한 무부식 기준시편의 인장실험 결과와 비교하여, 잔존두께와 표면형상이 부식강재의 항복하중, 인장하중 및 연신율에 미치는 영향을 정량화하였다. 그리고 부식의 유무에 상관없이 일정한 강재의 극한강도를 이용하여 무부식 등단면 강재와 동일하게 인장응력을 평가할 수 있는 불규칙 변단면 부식강재의 유효두께를 표면형상 측정결과로 산출한 평균잔존두께와 표준편차로 정식화하였다. 또한 이러한 결과를 실무에도 적용할 수 있도록 부식강재의 합리적인 잔존두께 측정간격도 제시하였다.

일본법상 외국중재판정의 승인집행 -적용법규와 승인집행거부를 중심으로- (Recognition and Enforcement of Foreign Arbitral Awards in Japan: Conventions, National law and Refusal of Recognition and Enforcement)

  • 김언숙
    • 한국중재학회지:중재연구
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    • 제20권3호
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    • pp.25-46
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    • 2010
  • In spite of great interest and recent innovation of the legislative system in the Arbitration and other Alternative Dispute Resolution(ADR) system, In Japan there have been only a few case in which International commercial dispute was settled through the Arbitration compared to other countries. However, we can easily expect that foreign arbitral awards which need to be recognized and enforced in Japan will gradually increase and this makes it very important for us to review the Japanese legislative system regarding recognition and enforcement of foreign arbitral awards. In this paper, I focused on the relations between applicable laws(including convention) regarding recognition and enforcement of foreign arbitral awards in Japan and some issues concerning refusal of recognition and enforcement of foreign arbitral awards. Japan is a member state of several multilateral conventions concerning recognition and enforcement of foreign arbitral awards including the New York Convention of 1958 and at least 20 bilateral agreements which include provisions in relate to the recognition and enforcement of arbitral awards. Therefore there are some legal issues about the priority application between multilateral and bilateral agreements in relate to Article 7(1) of the New York Convention. In Japan, as I mentioned in this paper, there are incoherent opinions concerning this issue. To solve it substantially it would seem appropriate to build up concrete and explicit provisions concerning the application of priority between multilateral and bilateral agreements. On the other hand, in relate to the application between the New York Convention and National Law, it is necessary to take general approach regarding the priority application between Convention (Treaty) and National Law, considering the national application of conventions under the Constitutional System of each country. Among the grounds for non-recognition/enforcement, there are the ones that are decided under the law of the requested country, for instance, arbitrability and public policy. It would therefore be possible that some foreign arbitral awards would not be recognized in Japan especially relating to the arbitrability because its scope in Japan is not so large. Regarding the enforcement of awards annulled in their place of origin, some positive opinions in recent Japanese legal discussions, say that annulled awards should be enforced as a counter strategy of developed countries and judiciary discretion of the requested country would be needed. As mentioned in this paper, the recognition and enforcement of foreign arbitral awards is closely related to judicial policy of the requested country as the recognition and enforcement of foreign judgment is. Even though there existed uniform rules on recognition and enforcement of foreign arbitral awards like the New York convention, each country has different internal legal status of conventions under its own Constitutional System and tends to interpret the provisions based in its own profit. Therefore, it is necessary to review, in the light of conflict of laws, the national legislative system including legal status of conventions of the requested countries concerning recognition and enforcement of foreign arbitral awards.

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S자형 환형덕트가 원심압축기 성능에 미치는 영향에 관한 연구 (A Study on the Influence of S Shaped Annular Duct on the Centrifugal Compressor Performance)

  • 정주현;전승배;김승우
    • 한국추진공학회지
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    • 제2권2호
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    • pp.64-73
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    • 1998
  • 항공기용 엔진에는 압축기단들 사이에 스트럿을 포함하는 S자형 환형덕트가 존재하기도 한다. 이러한 엔진에서 S자형 덕트를 통과하는 유동은 볼록면과 오목면을 따라 가면서 가속과 감속이 이루어지고, 벽면에서의 경계층 성장으로 인해 유로폐쇄량이 증가한다. 이처럼 S자형 덕트의 영향으로 후방에 존재하는 압축기는 불균일한 축방향 속도분포에 따른 영향을 받게 된다. 따라서, 후방 압축기는 전방에 위치한 S자형 덕트의 영향을 충분히 고려하여 설계하여야 한다. S자형 덕트가 미치는 영향을 고려하여 설계된 원심압축기의 성능을 검증하고, S자형 덕트가 원심압축기 성능에 미치는 영향을 파악해보기 위해 압축기 입구에 S자형 환형덕트를 장착한 경우와 원통형 덕트를 장착한 경우에 대해 각각 성능시험을 수행하였다. 시험결과를 통해 입구에 S자형 덕트가 있는 경우에는 없는 경우보다 압축비 및 효율 등 압축기 성능이 저하되고, 쵸킹유량이 감소함을 알 수 있었다. 이러한 성능저하의 원인을 분석하기 위해 S자형 덕트를 포함하는 임펠러의 유동해석을 수행하였으며, 그 결과 성능저하의 원인은, S자형 덕트와 임펠러의 상호작용으로 설계시 예측했던 것보다 인듀서팁에서 상대마하수가 증가하였고, 영각이 감소하였기 때문임을 확인할 수 있었다.

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Grouting diffusion mechanism in an oblique crack in rock masses considering temporal and spatial variation of viscosity of fast-curing grouts

  • Huang, Shuling;Pei, Qitao;Ding, Xiuli;Zhang, Yuting;Liu, Dengxue;He, Jun;Bian, Kang
    • Geomechanics and Engineering
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    • 제23권2호
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    • pp.151-163
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    • 2020
  • Grouting method is an effective way of reinforcing cracked rock masses and plugging water gushing. Current grouting diffusion models are generally developed for horizontal cracks, which is contradictory to the fact that the crack generally occurs in rock masses with irregular spatial distribution characteristics in real underground environments. To solve this problem, this study selected a cement-sodium silicate slurry (C-S slurry) generally used in engineering as a fast-curing grouting material and regarded the C-S slurry as a Bingham fluid with time-varying viscosity for analysis. Based on the theory of fluid mechanics, and by simultaneously considering the deadweight of slurry and characteristics of non-uniform spatial distribution of viscosity of fast-curing grouts, a theoretical model of slurry diffusion in an oblique crack in rock masses at constant grouting rate was established. Moreover, the viscosity and pressure distribution equations in the slurry diffusion zone were deduced, thus quantifying the relationship between grouting pressure, grouting time, and slurry diffusion distance. On this basis, by using a 3-d finite element program in multi-field coupled software Comsol, the numerical simulation results were compared with theoretical calculation values, further verifying the effectiveness of the theoretical model. In addition, through the analysis of two engineering case studies, the theoretical calculations and measured slurry diffusion radius were compared, to evaluate the application effects of the model in engineering practice. Finally, by using the established theoretical model, the influence of cracking in rock masses on the diffusion characteristics of slurry was analysed. The results demonstrate that the inclination angle of the crack in rock masses and azimuth angle of slurry diffusion affect slurry diffusion characteristics. More attention should be paid to the actual grouting process. The results can provide references for determining grouting parameters of fast-curing grouts in engineering practice.

입력 도메인 반복 분할 기법 성능 향상을 위한 고려 사항 분석 (Revision of ART with Iterative Partitioning for Performance Improvement)

  • 신승훈;박승규;정기현
    • 전자공학회논문지CI
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    • 제46권3호
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    • pp.64-76
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    • 2009
  • 적응적 랜덤 테스팅 (Adaptive Random Testing, ART) 기법 중 입력 도메인 반복 분할을 이용한 기법(ART through Iterative Partitioning, IP-ART)은 초기 ART 기법이 가지는 단점인 많은 거리 연산량을 입력 도메인 반복 분할 기법을 이용해 효율적으로 개선하였다. 또한 입력 도메인 확장을 이용한 IP-ART 기법(IP-ART with Enlarged Input Domain, EIP-ART)은 IP-ART가 가지는 특징을 효과적으로 이용해 IP-ART에서 보이는 테스트 케이스 분포 불균일 현상을 완화시켰으며, 다양한 환경에서 좋은 성능을 보인다. 하지만 EIP-ART는 입력 도메인 확장에 의해 발생되는 부수적인 부하로 인해 테스트 케이스 선택이 지연된다는 단점을 가진다. 이에 따라 본 논문에서는 입력 도메인의 확장 없이, IP-ART의 변화를 통한 성능 개선가능성 확인을 위해 테스트 케이스 분포에 영향을 줄 수 있는 세 가지 조건을 정의하고 이들 각각이 기법에 미치는 영향을 평가하였으며, 실험을 통해 정의된 세 가지 조건 중 제한 영역 관리 조건이 기법의 성능에 가장 긍정적인 영향을 주는 것을 확인하였다.