We examine a single machine scheduling problem with step-improving jobs in which job processing times decrease step-wisely over time according to their starting times. The objective is to minimize total completion time which is defined as the sum of completion times of jobs. The total completion time is frequently considered as an objective because it is highly related to the total time spent by jobs in the system as well as work-in-progress. Many applications of this problem can be observed in the real world such as data gathering networks, system upgrades or technological shock, and production lines operated with part-time workers in each shift. Our goal is to develop a scheduling algorithm that can provide an optimal solution. For this, we present an efficient branch and bound algorithm with an assignment-based node design and tight lower bounds that can prune branch and bound nodes at early stages and accordingly reduce the computation time. In numerical experiments well designed to consider various scenarios, it is shown that the proposed algorithm outperforms the existing method and can solve practical problems within reasonable computation time.

기존의 사후경과시간(PMI) 추정 방법은 대략적인 사후경과시간의 추정, 사후 48~72시간 경과 또는 부패 시 추정 불가능이라는 문제가 발생하여 최근에는 법의곤충학(Medicolegal entomology)을 통한 최소 사후 경과시간 (PMImin) 추정이 더욱 강조되고 있다. 이로 인해 시식성파리의 발육 성장속도 파악은 시체의 최소 사후 경과시간 추정에 있어 효과적인 도구로 활용될 수 있다. 본 연구에서는 곱슬털쉬파리(Parasarcophaga. similis)를 사육대상 종으로 선정하였다. P. similis는 부패한 시체를 섭식하는 시식성파리 중 하나로서, 발육 성장 속도에 따른 법곤충 학적(Forensic entomology) 최소 사후 경과시간을 추정하는 데 중요한 지표가 된다. 실험에 사용된 대상종의 경우, 경북 칠곡군 지천면 일대에서 6~9월경 야외쉬파리 채집하였고, 종 동정, 사육 및 증식, 예비 실험을 거친 후 본실험 을 진행하였다. 본실험은 산란 집단 케이지 내에서 산란 유도 후 12시간 간격으로 6개체를 샘플링하였고, 이를 Leica M125 Microscope (Leica Microsystems, Germany), EG-2HDNL(이지테크, Korea)로 이미지와 측정치를 확보 하였다. P. similis를 16~34°C 사이 7개의 온도 조건에서 성장 속도 측정을 3회 반복 실험하였으며, 곱슬털쉬파리의 최초 출현시점, 특정 온도 조건 별 발육 성장 속도 측정, 유충 몸길이 데이터, 이미지 자료, 표본 등을 확보하였다. 16, 19, 22, 25, 28, 31, and 34°C에서 P. similis의 알에서 성충까지의 발달 기간은 각각 822.0±5.9, 605.0±12.2, 442.3±9.4, 339.3±6.1, 289.3±7.5, 253.0±8.0, and 248.7±3.4h이 경과함을 확인하였다. 본 연구의 결과는 P. similis의 성장과정 데이터와 PMImin추정을 위한 지표로서 활용가능한 데이터를 제공한다.

The genus Peromitra Enderlein is a small group of phorid flies, including two European parasitic species known to parasitize larval bibionid flies. In this study, specimens of the Peromitra species collected from South Korea are examined morphologically on the basis of characteristics on ocellar region, leg chaetotaxy and hypopygium. As a result, four species are described new to science and two species, viz. P. fimbriata and P. multisetalis are newly recorded from South Korea. Photographs of diagnostic characters and a key to males of South Korean species are provided.

The genus Conicera Meigen is a group of necrophagous phorid flies mostly associated with carrion, including C. tibialis, commonly known as the “coffin fly” that breeds in buried corpses. In this study, specimens of the Conicera species collected from South Korea are examined morphologically on the basis of characteristics on male antennae, sensory organ on midfemora, and left and right surstyli on hypopygium. As a result, five species, viz. C. dauci, C. gracilis, C. orientalis, C. pacifica, C. quadrata are newly recorded from South Korea. Photographs of diagnostic characters, a distribution map and a key to males of South Korean species are provided.

컴퓨터 성능의 발전으로 빅데이터의 효율적인 사용이 가능해지면서, 심층 학습(deep learning)은 다양한 의료 분야에 활용할 수 있는 핵심적인 인공지능(artificial intelligence, AI) 기법으로 각광받고 있다. 이에 본 종설은 뇌종양 진단과 치료에 사용되는 자기공명영상(magnetic resonance imaging, MRI)의 심층 학습 기법을 소개하고자 하였다. 먼저 국내 AI의 의료 분야 도입의 동향을 분석하고, 이를 바탕으로 MRI를 활용한 뇌종양의 진단과 치료에 적용할 수 있는 심층 학습 기법과 그 결과들을 기술하였다. 뇌종양 진단과 치료 시, 심층 학습을 이용한 최근 사례는 영상 분류, 영상 품질 개선, 영상 분할로 나타났으며, 질병의 진단과 치료에 적용할 수 있는 객관적이고 높은 성능 수치를 나타내면서 그 유용성을 확인 할 수 있었다. 종합하자면, 심층 학습은 질병의 진단과 치료에 적용할 수 있는 유용한 지표이며, AI 역량을 지닌 의료진의 지도하에 점진적인 도입이 이뤄진다면 질병의 진단과 치료에 큰 도움을 주는 훌륭한 소프트웨어로 활용될 것으로 여겨진다. 본 종설이 심층 학습을 이해할 때 많은 도움이 되길 바라며, 향후 관련 연구를 수행할 때 가이드라인으로 활용될 것을 기대 한다.

This study investigated the residue of tulathromycin (TLM) on the lung tissue of pigs intramuscularly injected with 2.5 mg/kg body weight as a single dose. Nine healthy cross swine were intramuscularly injected with the drug. Three treated animals were arbitrarily selected to be sacrificed at 7, 10 and 14 days after treatment. TLM residue concentrations in lung tissue were determined using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The drug was extracted from lung samples using acetonitrile followed by clean-up with n-hexane. The analyte was separated on a Hypersil GOLDTM liquid chromatography column using 0.1% formic acid in deionized distilled water and acetonitrile. The correlation coefficient (R2) of the calibration curve was 0.9981, and the limits of detection and quantification were 10 and 50 μg/kg, respectively. Recoveries at three spiking levels ranged between 95.0-98.2%, and relative standard deviations were less than 3.95%. In TLM-treated group, the concentration of TLM on 7, 10 and 14 days post-treatment was 627.3, 496.9, 259.1 μg/kg, respectively. The developed method is sensitive and reliable for detection of TLM in porcine lung tissues. In addition, it can detect below the maximum residue limits in animal-derived food products destined for human consumption.

Clostridium perfringens (C. perfringens) may cause diarrhea and enterotoxemia in adult and young livestock, leading to problems in the production and management of farms. Four hundred fecal samples were collected from 25 goat farms located in Gyeongsangbuk-do Province in the Republic of Korea. Sixteen C. perfringens strains were isolates from fecal samples, and the isolates were identified as type A (n=11) and type D (n=5). Additionally, α- and ε-toxin genes were detected in 16 and 5 strains by PCR, respectively, and the enterotoxin gene was presented in 2 strains. The antibiotic susceptibility test was performed using the disk diffusion method and E-test method. In the disk diffusion method, ampicillin (n=16) and chloramphenicol (n=15) were highly susceptible to 16 C. perfringens isolates. In the E-test method, ampicillin, amoxicillin, amoxicillin/clavulanic acid and meropenem were susceptible to more than 14 of 16 C. perfringens isolates. This study indicates that administration of antibiotics such as ampicillin, amoxicillin/clavulanic acid and meropenem can prevent and treat C. perfringens infections in goats.

In this study, the microstructure was confirmed by examining the exoskeleton of Cybister japonicus and Hydrophilus acuminatus, which are representative aquatic insects. And the exoskeleton was observed through the microscope. The digestive organs and respiratory organs were observed through anatomy, respectively. Hydrophilus acuminatus had longer midgut and hindgut than Cybister japonicus, and Cybister japonicus had larger crop than Hydrophilus acuminatus. The structural difference of the hind legs revealed that there was a difference between their swimming behavior. Cybister japonicus swing both legs at the same time, while Hydrophilus acuminatus swings alternately on both hind legs. This study is expected to be the basis of ecological studies and researches of aquatic insects by studying the basic structure of aquatic insects.

Calcium-hexaluminate phase is known to be effective for the crack shielding due to the spinel block crystal structure. In this study, we focused to the control of morphology for good damage tolerance behavior in alumina and zirconia/calcium-hexaluminate composites. Calcium-hexaluminate composites were prepared from zirconia, alumina and calcium carbornate powders. Calcium-hexaluminate phase was obtained by the solid reaction through the formation of intermediate phase . phase showed the column type abnormal grain grown behavior composed of small blocks. Due to the typical microstructure of , alumina and zirconia/calcium-hexaluminate composites provide a well controlled crack propagation behavior.

In gamma-ray spectrometry for volume samples, the self-attenuation effect should be considered in the case of differences in chemical composition and density between the efficiency calibration source for quantitative analysis of sample and the sample actually measured. In particular, the lower the gamma-ray energy, the greater the gamma-ray attenuation due to the self-attenuation effect of the sample. So, the attenuation effect of low-energy gamma-rays in the sample should be corrected to avoid over- or under-estimation of its radioactivity. One of the most important factors in correcting the self-attenuation effect of the sample is the linear attenuation coefficient for the sample, which can be directly calculated using a collimator. The larger the size of the collimator, the more advantageous it is to calculate the linear attenuation coefficient of the sample, but excessive size may limit the use of the collimator in a typical environmental laboratory due to its heavy weight. Therefore, it is necessary to optimize the collimator size and structure according to the measurement environment and purpose. This study is to optimize a collimator that can determine the effective linear attenuation coefficient of low-energy gamma-rays, and verify its applicability. The overall structure of the designed collimator was optimized for gamma-ray energy of less than 100 keV and cylindrical plastic bottle with diameter of 60 mm and a height of 40 mm. The materials of optimized collimator consisted of tungsten. Acryl and acetal were used to form the housing of the collimator, which fixes the central axis of the bottle, collimator and point-like source. In addition, using the housing, the height of the tungsten is adjusted according to the height of the sample. For applicability evaluation of the optimized collimator, IAEA reference material in solid form were used. The sample was filled in the bottle with heights of 1, 2, 3 and 4 cm respectively. Using the collimator and point-like source of 210Pb (46.5 keV), 241Am (59.5 keV), and 57Co (121.1 keV), the linear attenuation coefficient and the radioactivity for the samples were calculated. As a result, to calculate the linear attenuation coefficient using the optimized collimator, a relatively high sample height is required. However, the optimized collimator can be used to determine the linear attenuation coefficients of low-energy gamma-rays for the self-attenuation correction regardless of the sample height. It is concluded that the optimized collimator can be useful to correct the sample selfattenuation effect.