• Title/Summary/Keyword: Sweet spot

Search Result 56, Processing Time 0.031 seconds

DEEP-South: Performance of Moving Object Detection Program in Different Observation Modes

  • Oh, Young-Seok;Bae, Yeong-Ho;Kim, Myung-Jin;Roh, Dong-Goo;Jin, Ho;Moon, Hong-Kyu;Park, Jintae;Lee, Hee-Jae;Yim, Hong-Suh;Choi, Young-Jun
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.41 no.2
    • /
    • pp.48.3-49
    • /
    • 2016
  • We have five different types of observation modes with regard to the Deep Ecliptic Patrol of the Southern Sky (DEEP-South); Opposition Census (OC) for targeted photometry, Sweet Spot Survey (S1) for discovery and orbit characterization of Atens and Atiras, Ecliptic Survey (S2) for asteroid family studies and comet census, NEOWISE follow-up (NW) for near simultaneous albedo measurements in the visible bands, and Target of Opportunity (TO) observation for follow-up either for unpredictable events or targets of special interests. Different exposures with such different modes result in a wide range of background noise level, the number of background stars and the mover's projected speed in each image. The Moving Object Detection Program (MODP) utilizes multiple mosaic images being taken for the same target fields at different epochs at the three KMTNet sites. MODP employs existing software packages such as SExtractor (Source-Extractor) and SCAMP (Software for Calibrating Astrometry and Photometry); SExtractor generates object catalogs, while SCAMP conducts precision astrometric calibration, then MODP determines if a point source is moving. This package creates animated stamp images for visual inspection with MPC reports, the latter for checking whether an object is known or unknown. We evaluate the astrometric accuracy and efficiency of MODP using the year one dataset obtained from DEEP-South operations.

  • PDF

MR Technology to 4T

  • Vaughan, Thomas
    • Proceedings of the KSMRM Conference
    • /
    • 2003.10a
    • /
    • pp.103-105
    • /
    • 2003
  • After fifteen years of development, Magnetic Resonance (MR) technology for human imaging and spectroscopy is reaching a refined state with FDA approved 3T clinical products from Siemens, GE, and Philips. Broker has cleared CE approval with a 4T system. Varian supports a 4T system platform as well. Shielded magnets are standard at 3T from GE, Oxford, Magnex, and IGC. A shielded 4T whole body magnet is available from Oxford. Stronger switched gradients and dynamic shim coils, desired at any field, areespecially useful at higher static magnetic fields B0. In addition to the higher currents required for higher resolution slice or volume selection afforded by higher SNR, whole body gradient coils will be driven at increasing slew rates to meet the needs of new cardiac applications and other requirements. For example 3T and 4T systems are now being equipped with 2kV, 500A gradient coils and amplifiers capable of generating 4G/cm in 200msec, over a 67+/-cm bore diameter. High field EPI applications require oscillation rates at 1 kHz and higher. To achieve a benchmark 0.2 ppm shim over a 30cm sphere in a high field magnet, at least four stages of shimming need to be considered. 1) A good high field magnet will be built to a homogeneity spec. falling in the range of 100 to 150 ppm over this 30cm spherical "sweet spot" 2) Most modern high field magnets will also have superconducting shim coils capable of finding 1.5 ppm by their adjustment during system installation. 3) Passive ferro-magnetic shimming combined with 4) active, high order room temperature shim coils (as many as five orders are now being recommended) will accomplish 0.2 ppm over the 30cm sphere, and 0.1 ppm over a human brain in even the highest field magnets for human studies. Safety concerns for strong, fast gradients at any B0 field include acoustic noise and peripheral nerve stimulation. One or more of the mechanical decoupling methods may lead to quieter gradients. Patient positioning relative to asymmetric or short gradient coils may limit peripheral nerve stimulation at higher slew rates. Gradient designs combining a short coil for local speed and strength with a longer coil for coverage are being developed for 3T systems. Local gradients give another approach to maximizing performance over a limited region while keeping within the physiologically imposed dB0/dt performance limits.

  • PDF

Occurrence of diseases and insects in organic sweet corn seed production area (유기농 옥수수종자 생산지의 병해충 발생 소장)

  • Kim, Jeong-Soon;Goh, Byeong-Dae;Kim, Chang-Yung;Gwag, Jae-Gyun;Shim, Chang-Ki
    • Proceedings of the Korean Society of Organic Agriculture Conference
    • /
    • 2009.12a
    • /
    • pp.292-292
    • /
    • 2009
  • 본 연구는 유기종자 안전 생산기술 개발을 위한 효과적인 병해충 제어를 위해 대표적인 찰옥수수 품종인 미백2호와 흑미찰을 대상으로 병?해충 발생양상을 조사하였다. 2008년 유기농 찰옥수수 종자 생산지의 우점 비산포자의 종류 중Alternaria sp., Cladosporium sp., 및 Helminthosoprium sp.,은전 생육기간에 관찰되었다. 또한종자로부터 신초 출현 전후로 종자가 발아하지 않고 부패하거나 유묘의 시들음 증상, 심하면 고사하는 증상과 거세미나방에 의해 지재부가 절단된 전형적인 피해를 관찰할 수 있었고 발병주율은 14~6% 미만이었다. 특히, 포장내 조명나방 발생밀도는 2008년 트랩당 3.5~0.5 마리로 높게 나타났으며, 2009년 트랩당 0.5~6마리로 낮게 나타났다. 또한 피해주율은 2008년은 7.5(미백2호)~21(미흑찰)%였으며, 2009년은 1~46%로 매년 높은 피해주율을 보였으며 수확기까지 지속적으로 증가하였다. 옥수수잎마름병 (Leaf blight)의 발생 양상은 2008년도에 7%(미흑찰)~34%(미백2호)로 높게 나타났으며, 2009년은 6월18일 이후 초발생하여 발병주율이 8월 21일 (59%, 미흑찰)이후 급격히 증가하여 9월 25일이는 미흑찰 (69%)의 발병주율이 미백2호 (56%)보다 높게 나타났다. 옥수수깜부기병(Common Smut)의 발생 양상은 2008년도에 20주 중 2%~15%의 발병주율을 보였으며, 2009년은 초발생 시기가 7월17일로 2008년에 비해 17일 정도 늦추어졌으며 발병주율도 8% 미만 (9월 25일)으로 2008년에 비해 아주 낮게 나타났다. 옥수수깨씨무늬병 (Southern Leaf Spot)의 발생 양상은 2008년 20주 중 초기에 평균 11%(미흑찰)에서 증가하여 9월 19일 조사시에는 두 품종 모두 62%로 높게 나타났다. 2009년은 6월8일 이후 초발생하였으며 9월 25일까지 지속적 발병하여 약 86%의 발병 주율을 보였고 2008년에 비해 24% 이상 발병주율이 높았다.

  • PDF

Changes of Various Balls Velocity under the Different Surface Conditions after Impact (충돌 후 지면 조건에 따른 다양한 볼의 속도변화에 관한 연구)

  • Park, Jin
    • Korean Journal of Applied Biomechanics
    • /
    • v.17 no.1
    • /
    • pp.91-97
    • /
    • 2007
  • The purpose of this study was to investigate the changes of various balls velocity under the different surface conditions after impact. For this study, four different balls were used which are golf ball, tang-tang ball, table tennis ball, and iron ball. And two different types of ground conditions were used which are artificial grass green and glass green. Movements of putter head and ball were recorded with 2 HD video cameras(60 Hz, 1/500s shutter speed). Small size control object($18.5cm{\times}18.5cm{\times}78.5cm$) was used in this study. To transfer the same amount of kinetic energy to the ball, pendulum putting machine was used. Analyzing the process of impact and the ball movement, a putter was digitized the whole movement but the ball was digizited within the 50cm movement. Velocities were calculated by the first central difference method(Hamill & Knutzen, 1995). Putter head velocities were about 112.2cm/s-116.2cm/s at impact. Maximum ball velocities were appeared 0.08s-0.10s after impact no matter what the ground conditions are. Table tennis ball recorded higher ball velocities than the other ball velocities and iron ball recorded the lowest ball velocity in this group. But Table tennis ball was influenced with the frictional force and immediately was decreased at the artificial grass green condition. If an object is received the kinetic energy under the static condition(v=0cm/s), the object recorded the maximum velocity shortly after the impact and then decreased the velocity because of the frictional force. The ball distance from the start position to the peak velocity position is about 6cm-10cm under the 112.2cm/s-116.2cm/s putting velocity with putter. 0.25 seconds later after impact balls were placed 40cm distance from the original position except iron ball. In this study, ball moving distances were too short therefore it was not possible to investigate the reactions after the translational force is disappeared. Rotational force would play a major role at the end of the ball movement. Future study must accept two things. One is long distance movement of ball and the other is balanced ground. Three-piece ball is a good item to investigate the golf ball movement on the different surface conditions.

A Study of Power Perception between Supplier and Retail Buyer of Agricultural Products (농산물공급자와 대형소매업체 바이어간의 상호 파워 인식에 대한 연구)

  • 서성무;이은정
    • Proceedings of the Korean DIstribution Association Conference
    • /
    • 2003.02a
    • /
    • pp.123-166
    • /
    • 2003
  • Marketing channel is recognized as one of the society systems which have the character of functional organization. These organizations are related to each other for specialized and cooperative work. Channel members in distribution channel are striving to accomplish exchange through reciprocal action. Thus channel members exercise their power to take better position in exchange. There will be struggling between members about satisfaction and conflict during this power exercise. Now a days, buyers use more harsh power as large retail firms are increasing. This phenomenon is occurring in the distribution channel. However, there will be different phenomenon in case of agricultural products. Not like industrial product suppliers, agricultural product suppliers have various supply channels and many agricultural products are seasonal. It has also unstable amount supplies. There should be differentiated marketing in agricultural products. Relatively weaker powered suppliers have to strengthen comparative factors and also have to be technically specialized through assessed experience in order to establish strong product sales chain. Making a brand of agricultural product would be also a good idea to increase the product comparability. Channel members need to be recognized their specialized functions in order to make balanced distribution channel. There have to be conversion of concept of relation between suppliers and buyers from subordinate relationship to cooperative relationship.

  • PDF

A Study on Patterns of Sap Water Users of Acer mono (고로쇠나무 수액(樹液) 이용객(利用客)의 음용형태(飮用形態)에 관(關)한 연구(硏究))

  • An, Jong Man;Kim, Jun Sun;Kang, Hag Mo
    • Journal of Korean Society of Forest Science
    • /
    • v.87 no.4
    • /
    • pp.510-518
    • /
    • 1998
  • This study was carried out to investigate the drinking patterns of sap water of Acer mono by on-the-spot visitors. The survey was done from late-February to mid-March in the 3 major sap water tapping regions, such as Piagol of Mt. Chiri in Kurey, Okryong of Mt. Baekun in Kwangyang, and Mt. Chokey in Sunchon, Chonnam. A total of 300 visitors over 20 years old, 100 visitors in each region, were interviewed personally to make up questionnaires, irrespective of sex. The purpose of drinking, the frequency of visit, the modes of traffic, the length of stay, drinking amount per person, one's opinions after drinking, drinking plans and patterns, and intention of drinking processed sap were investigated and examined. Wide range of age groups from twenties to sixties drank sap water. Visitors drank sap water in order to keep health, to promote mutual friendship, and so on. 44% of sap drinkers visited for the first time, and 71% visited by private automobiles holding the first place. 59.7% of visitors spent only a day, but 40.3% passed one or two nights to drink sap water. For drinking amount of sap water, $3-6{\ell}$ a was consumed by 31.3% of visitors, under $3{\ell}$ or $9-12{\ell}$ by 22.7% $6-9{\ell}$ by 12.7% and so forth. 74% of visitors felt sap water sweet and favorable, but were doubtful about the efficacy of sap water. 79.0% of visitors had a plan to drink sap water again next year, 40% of whom preferred a day's visit to overnight staying (29%) or 3 days' staying (6%). 45% answered to plan to drink sap water with having meals, and 43% with having meals and passing a night. More than half (54.3%) of the visitors were inclined not to drink processed sap water for the reasons of unreliable quality, unwillingness for process, change in quality, etc.

  • PDF