Resistance Factor Calculations for LRFD of Axially Loaded Driven Piles in Sands

김동욱,정문경,곽기석 대한토목학회 2011 KSCE Journal of Civil Engineering Vol.15 No.7

This paper presents the development of Load and Resistance Factor Design (LRFD) of axially-loaded driven piles in sands. The resistance factors of base and shaft resistances were calculated separately to account for their different uncertainty levels. The ratios of dead-to-live load and ultimate base resistance to limit shaft resistance change the uncertainty levels of total load and total pile capacity, respectively; thus, those ratios should be reflected in the calculation of base and shaft resistance factors. For the development of LRFD for axially-loaded driven piles in sands, the ultimate limit state for an axially-loaded driven pile was established based on the Imperial College Pile (ICP) design method; the uncertainties of loads and resistance were accessed;reliability analyses were performed using the First-order Reliability Method (FORM); and finally, reasonable resistance factors of base and shaft resistances were calculated based on the results of reliability analyses for different target reliability index levels. The load factors used for the calculation of resistance factors are the ones proposed by AASHTO and ASCE/SEI 7-05. From the results of extensible reliability analyses using FORM, the resistance factors for base and shaft resistances were found to be highly dependent on the ratios of the dead-to-live load and the ultimate base resistance to the limit shaft resistance. Resistance factors are proposed for different combinations of these ratios within their possible ranges.

고강도 저항성 운동이 24시간 평균동맥압과 심박수에 미치는 영향

박철호,우상헌 東亞大學校附設스포츠科學硏究所 2002 스포츠科學硏究論文集 Vol.20 No.-

As this study is to examine the effect of resistance exercise, it was made an experiment on resistance-trained group which conducted more than three times a week during 12 weeks and high-intensity resistance exercise of once during 60 minutes in the object of a young man in his 20s with normotensive and irregular exercise habit. After the exercise, MAP and heart rate(HR) during 24-h were changed as the following results. 1. On rest HR of resistance-trained group compared with non-trained group were significantly(p<.05) low, MAP of resistance-trained group compared with non-trained group were low but they were not significantly different. 2. The change of 24-h HR in resistance-trained group both resistance exercise day and control day didn't have the significant difference in all sections. 3. 24-h HR of non-trained group was significantly(p<.05) low between 9AM to 1PM on resistance exercise day compared with control day. 4. On control day, HR of resistance-trained group compared with non-trained group were significantly(p<.05) low between 9AM to 1PM. 5. On resistance exercise day, 24-h HR of resistance-trained group compared with non-trained group were significantly(p<.05) low, 24-h MAP is significantly(p<.05) high between 9AM to 1PM. In conclusion, rest heart rate(RHR) of resistance trained group were significantly(p<.05) low compared with mean, cardiovascular's function of resistance trained group compared with non-trained group were good. In all comparisons, 24-h heart rate(HR) and MAP were similar patterns, it showed they didn't have an influence on the change of 24-h blood pressure(BP) no matter how resistance exercise may be executed.

Inheritance pattern and expression of resistance to phosphine in larval stage of Tribolium castaneum (Coleoptera: Tenebrionidae)

Ramya R.S.,Srivastava Chitra,Subramanian Sabtharishi,Ranjith M. 한국응용곤충학회 2023 Journal of Asia-Pacific Entomology Vol.26 No.1

Resistance developed by Tribolium castaneum (Herbst), a major pest of stored grain and grain products, to phosphine is a serious concern. Treatment of phosphine is given to all the stages (egg, larva, pupa and adult) of insects simultaneously in the infected commodity. Effective resistance management tactics need a proper un derstanding of expression of resistance in relation to dosage in immature stages including larvae. So, this study was undertaken to understand the genetic basis of phosphine resistance in larval stage of T. castaneum by crossing the resistant and susceptible parents to obtain the F 1 , F 2 and the back-cross progenies. The resistant parent had a resistance ratio of 37.75 when compared to the susceptible parent. The susceptibility levels of the reciprocal F 1 hybrids did not show any significant difference indicating autosomal mode of inheritance of resistance. Level of dominance for the reciprocal F 1 hybrids was estimated (-0.70 and − 0.68) which showed that the resistance is expressed as incompletely recessive in larval stage of T. castaneum. χ 2 analysis showed that the observed and expected mortalities differed significantly (P < 0.05) in most of the concentrations indicating that more than one gene is responsible for phosphine resistance. Two plateaus at ~ 40 % and ~ 90 % mortality levels for the backcross progeny to the resistant parent further confirmed the involvement of two or more genes in imparting resistance to phosphine. Our results will aid in enhancing the knowledge on the development of resistance to phosphine in the field and thus facilitate in designing suitable resistance management tactics.

Strategy for Insecticide Resistance Management Approach to IPM

Motoyama, Naoki,Dauterman, W.C. Korean Society of Applied Entomology 1992 한국응용곤충학회지 Vol.31 No.3

Insecticide resistance is a serious is a serious threat to IPM, resulting in various adverse effects not to mention the loss of yield in agriculture. One approach to counter the problem is the disruption of resistance mechanisms. This can be achieved by (1) compounds which show a negative correlation with resistance at the site of action, (2) specific metabolic inhibitors which serve as synergists, or (3) a certain combination of two insecticides producing a joint action. This approach, however, requires certain precautions for the side effects may cause an increase in toxicity to mammals. Owing to the recent advances in theoretical studies on resistance management employing computer simulation and mathematical models, a few principles to reduce the risk of development of resistance have been clarified. They are helpful in designing operational strategies with regard to, for instance, insecticide doses to be applied, mode of application, and choice and nature of the insecticide(s) to be used. For restoration of insecticide susceptibility of a resistant population, reintroduction of susceptible individuals to the resistant population is feasible when certain conditions are met. Natural enemies which developed resistance to insecticides can be an important component of IPM as has been shown in the pest management in apple orchards. After all, the implementation of a successful resistance management program depends upon cooperation between different sigments of the agricutural community. Although resistance is a preadaptive phenomenon, in some cases spontaneous loss of resistance does occur without contamination by susceptible individuals. The instability of resistance in these insects implies the possible existence of a switch machanism controlling the expression of resistance gene(s). Elucidation of such a mechanism may eventually provide us with a new technical approach with which we can combat the problem of insecticide resistance.

특집 : 북한 주민의 ``일상의 저항``: 저항 유형과 체제와의 상호작용

조정아 ( Jeong Ah Cho ) 동국대학교 북한학연구소(구 동국대학교 안보연구소) 2011 북한학연구 Vol.7 No.1

이 글에서는 북한 주민들의 일상적 행위양식의 특성을 ``일상의 저항``이라는 관점에서 살펴보고, 주민들의 저항과 이에 영향을 미치는 제도적·구조적 조건과의 상호작용에 관해 탐구하였다. 최근 북한 사회에서는 일상적 불평불만 표출, 생존전략으로서의 일탈 및 위법행위, 회피적 저항과 같은 세 가지 유형의 일상의 저항이 나타나고 있다. 북한 사회에서 집단적이고 공개적인 저항보다 일상의 저항이 주를 이루고 있는 것은 강력한 통제·억압 기구가 발달해 있으며, 이데 올로 기적 통제기구, 각종 의례와 문화적 상징 등이 주민들의 의식을 형성, 재생산하고 있기 때문이다. 일상의 저항은 생존전략 차원의 저항인 동시에 변형된 체제순응 행위이기도 하다는 이중성을 지닌다. 저항의 목적은 국가 체제 또는 지배관계 자체의 변화라 기보다는 일상적 요소의 개선, 일상생활의 유지, 생존과 같은 것이다. 또한 생산과 재생산의 영역에서, 행위와 사회적 관계와 의식의 차원에서, 지배와 일상의 저항은 편재해 있고 동시적으로 작동한다. 이와 같은 특성으로 인해 일상의 저항이 체제에 미치는 영향은 복합적이다. 일상의 저항은 단기적, 국지적으로는 사회의 불안정을 증가시키는 요소이지만, 장기적, 총체적으로는 체제를 안정시키는 작용을 할 수도 있고, 이와 달리 특정한 역사적 계기를 만나 적극적인 집단적 저항으로 진화할 수 있는 가능성도 내포하고 있다. This paper reviews the features of North Korean`s daily patterns of behavior from the standpoint of ``everyday resistance`` and investigates the interaction between resistance and institutional and structural conditions which influence it. Recently throughout North Korean society, three major forms of resistance have begun to loom large: the routine expression of complaints, the adoption of deviant or illegal acts as survival strategies, and the practice of evasive resistance. The reason why this everyday resistance is more prevalent in North Korean society today as opposed to any sort of collective, open resistance is because North Korea has developed powerful structures of repression and control and because its ideologically controlled organizations, rituals, and cultural symbols have built up and reconstructed the peoples` consciousness. Everyday resistance has a dual character in the sense that it is both a survival strategy and a modified form of system adaptation. Instead of demanding changes per se to the ruling system, the objective of resistance is to improve everyday conditions, to support daily life, and to survive. In the areas of production and reproduction, and in terms of behavior, social relationships, and consciousness, forms of resistance against the ruling power and the daily routine are omnipresent and work together simultaneously. Thus, due to these characteristics, acts of everyday resistance affect the North Korean system in complex ways. While everyday resistance can be a factor in increasing social instability in short-term at the local level, it can also act to stabilize the system overall on a more long-term basis. On the other hand, it is possible that everyday resistance may encounter certain historical events that cause it to develop into a more aggressive, collective form of resistance.

Molecular Marker Development and Gene Cloning for Diverse Disease Resistance in Pepper (Capsicum annuum L.): Current Status and Prospects

Geleta Dugassa Barka,이준대 한국육종학회 2020 Plant Breeding and Biotechnology Vol.8 No.2

The production of chili pepper (Capsicum annuum L.) is hindered by several biotic factors even though stridingprogresses were made in genetic improvement in the last two decades. Among the advancements were the fast-track geneticimprovement of disease-resistant varieties by the use of marker-assisted selection (MAS) and the conventional breeding-based introgressionof major resistance genes. Marker development, marker-based identification and fine mapping have revealed a large numberof resistance genes, from which cloning of some candidate genes demonstrated the applicability and versatility of map-based cloningfor disease resistance. In some of the recent fine mapping of disease resistance QTLs, closely linked DNA markers were identified,which in turn resulted in the rapid introgression of target gene(s) into breeding lines. Also, progresses were made on the characterizationand map-based cloning of resistance genes conferring broad-spectrum resistance. As the number of identified and characterizedresistance genes and the DNA markers linked to resistance genes are steadily generated, the development of multiple/durable resistanceto major chili pepper diseases is accelerated by MAS. In the present review, the development of molecular markers, marker-basedmapping of genes conferring resistance to ten major chili pepper diseases were discussed, focusing on the recent advancements in majorand QTL-spanning resistance gene mapping. The review provides up-to-date insights into the development of DNA markers linked todisease resistance genes and the cloning of resistance genes, which are all so crucial in pepper breeding for disease resistance.

하한지지력이 현장타설말뚝의 저항계수에 미치는 영향

김석중,박재현,김명모 한국지반공학회 2014 한국지반공학회논문집 Vol.30 No.11

Load and Resistance Factor Design (LRFD) is one of the limit state design methods, and has been used worldwide,especially in North America. Also, the study for LRFD has been actively conducted in Korea. However, the data forLRFD in Korea were not sufficient, so resistance factors suggested by AASTTO have been used for the design in Korea. But the resistance factors suggested by AASHTO represent the characteristics of bedrocks defined in the US, therefore,it is necessary to determine the resistance factors for designs in Korea, which can reflect the characteristics of bedrocksin Korea. Also, the calculated probabilities of failure from conventional reliability analyses which commonly uselog-normal distribution are not realistic because of the lower tail that can be extended to zero. Therefore, it is necessaryto calibrate the resistance factors considering the lower-bound resistance. Thus, this study calculates the resistance factorsusing thirteen sets of drilled shaft load test results, and then calibrates the resistance factors considering the lower-boundresistance corresponding to a target reliability index of 3.0. As a result, resistance factors from conventional reliabilityanalyses were determined in the range of 0.13-0.32 for the shaft resistance, and 0.19-0.29 for the base resistance,respectively. Also, the lower bounds of resistance were determined based on the Hoek-Brown failure criteria (2002)and GSI downgrading. Considering the lower-bound resistances, resistance factors increased by 0~8% for the shaft,and 0~13% for the base, respectively.

Methicillin-내성 황색포도상구균의 각종 항균제에 대한 내성양상과 Plasmid DNA의 특성

정선식,신종희,류필열,안태휴,양동욱,김영일,이준행,김영휴 대한감염학회 1995 감염 Vol.27 No.1

광주지역의 A병원과 B병원에 입원한 환자의 각종 임상가검물로 부터 분리동정한 황색포도상구균 251주를 19종의 항균제에 대한 감수성 검사를 실시하고 내성인자를 조사하여 다음과 같은 결과를 얻었다. Oxacillin에 대한 내성빈도는 A병원에서 74.2%로 B병원의 46.1% 보다 약 30% 정도가 높았다. 또한 cephalosporine계 항균제와 aminoglycoside계 약제에 대한 내성빈도는 A 병원 분리균주에서 높은 경향을 보였으며, ampicillin(Amc), tetracycline(Tc), chloram-phenicol(Chp), ciprofloxacin(Cpfx)등의 항균제에 대한 내성빈도는 A병원와 B병원에서 분리된 균주간에 유사하였다. 그러나 fosfomycin(Fom)에 대한 내성빈도는 오히려 B병원 분리균주에서 높았다. 10가지 이상의 약제에 내성을 갖는 다제내성균의 출현율은 B병원에서 보다 A병원에서 높았다. A병원와 B병원에서 분리된 MRSA 대부분이 cefamandole(Cmdl)을 제외한 cephalosporin계 약제와 aminoglycoside제제에 대해 내성을 나타내었으며, netilmicin(Net) 과 rifampin(Rfp)에 대한 내성빈도는 A병원에서 분리된 균주에서 높았으며 Fom, Tc, Chp에 대한 내성빈도는 오히려 B병원에서 분리된 MRSA 에서 높았다. 다제내성균의 출현율은 두 병원간에 큰차이가 없었다. MRSA 의 다제내성양상은 Fom, Net, Chp 및 Rfp에 대한 내성에 따라 A병원와 B병원에 서 분리된 균주간의 차이가 관찰되었는데, A병원에서 가장 많이 나타난 내성유형은 AmcCtxCzolLmoxGmTobLcmAmkNetTcEmRfp 및 AmcCtxCzolCmdlLmoxFomGmTobLcmAmkNetTcEmRfp에 중복내성을 갖는 균주가 각각 12균주로 가장 많았으며 B병원에서 분리된 균주에서 많이보이는 내성유형은 AmcCtxCzolLmoxFomGmTobLcmAmkChpTcEm에 중복내성은 갖는 균주가 11주로 가장 많았다. 두 병원에서 분리된 균주 모두 β-lactam계 약제와 aminoglycoside계 약제간의 교차내성을 가지고 있었다. MRSA균주에서 분리한 plasmid DNA profile은 A병원와 B병원에서 분리된 균주에서 약제에 대한 다제내성양상에 따라 차이가 있었으며, A병원 분리균주에서는 108kb, B병원 분리균주에서는 2.8kb의 plasmid를 보유하는 차이가 있었다. Background: Increased isolation of methicillin-resistant Straphylococcus aureus has become one of the important problem in treating staphylococcal infections. The aim of the study was to investigate the epidemiological characteristics of antimicrobial resistance of MRSA's isolated in the Kwangju area. Methods: 251 strains of S. aureus were isolated from various specimens from A-hospital and B-hospital and there resistance patterns against 19 antimicrobial agents and plasmid profiles studied. Results: Methicillin resistance was detected in 74.2% and 46.1% of A-hospital and B-hospital isolates, respectively. Resistance to cephalosporins and aminoglycosides was more frequent in the A-hospital isolates than in the B-hospital isolates, whereas fosfomycin resistance was more frequent in the B-hospital isolates than in the A-hospital isolates. Frequency of resistance to ampicillin, tetracycline, chloramphenicol, ciprofloxacin in A-hospital isolates was similar to B-hospital isolates. Strains with multiple resistance to more than 10 drugs were more frequent in the A-hospital isolates than that in the B-hospital isolates. Among MRSA strains, resistance to netilmicin and rifampin was more frequently encountered in A-hospital isolates, while resistance to fosfomycin, tetracyclin, and chloramphenicol was more frequent in B-hospital isolates. No differences in resistance patterns against other cephalosporins and aminoglycosides were observed between the two hospitals. Fosfomycin, netilmicin, chloramphenicol and rifampin resistances were different between the hospitals in strains with multiple resistance. The most frequently observed multiple resistance patterns observed among A-hospital isolates were AmcCtxCzoILmoxGmTobLcmAmkNetTcEmRfp and AmcCtxCzolCmdlLmoxFomGmTobLcmAmkNetTcEmRfp. Among B-hospital isolates, AmcCtxCzolLmoxGmTobLcmAmkChpTcEm pattern was the most frequent. Conclusion: MRSA strains from both hospitals showed cross-resistance to β-lactams and aminoglycosides. Plasmid profiles from MRSA strains were different, according to the multiple resistance patterns. Characteristically, 108 kb plasmid was detected only in A-hospital-MRSA strains, while 2.8 kb plasmid was detected only in B-hospital-MRSA strains.

Current advances and prospectus of viral resistance in horticultural crops

염인화 한국원예학회 2016 Horticulture, Environment, and Biotechnology Vol.57 No.2

Viruses are a major threat causing massive yield loss and economical damage to crop production worldwide. Through complex evolutionary processes, plants encounter and overcome viral infection by developing effective resistance mechanisms. Over the past decade, remarkable progress has been made in understanding the nature of plant resistance to viruses at the molecular level. This review summarizes the major resistance strategies that plants use to prevent viral infection. Recent investigations suggest that antiviral RNA silencing is the most prevalent defense strategy in plants. Other forms of resistance include R gene-mediated resistance and host factor-related recessive resistance. Naturally occurring resistances arise and are maintained in numerous virus-plant pathosystems based mainly on arms-race relationships and the cost-efficiency of resistance acquisition. In addition to the current status of the known resistance mechanisms, this review discusses the future prospectus for the practical application of plant resistances that influence resistance durability in agricultural ecosystems. Such applications include molecular breeding strategies using advanced molecular marker systems and the utilization of trans- or cis- genetics via the acquisition of engineered disease resistances.

Electrical Resistance Evaluation Reliability under High Grade Temperature for Na-AMTEC(Natrium Alkali-Metal Thermal-to-Electric Convertor)

Min-Soo SUH(서민수) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4

In general, an electrical circuit, electrical resistance is a measure of the opposition to current flow. Resistance is a measured in ohms, symbolized by the Greek letter omega(Ω). In practical, specialized on Na-AMTEC(Natrium Alkali-Metal Thermal-to-Electric Convertor), the input energy is directly converted to electrical energy. In microscopic view, the energy transforming of one source to another useful forms classified as storage, transportation and conversion is simultaneous taken place in one small circuit. In macroscopic view, thermal energy directly converted into electrical energy, in other words it is energy transforming primarily solar-to-thermal and thermal-to-electric. In case of metallic substances, free electrons are moving randomly in the crystal structure of it. Due mainly to the electric field across the resistance, free electrons drift from lower potential point to higher potential when voltage is applied. Free electron continually collides with atoms of the substance during drifting motion, this phenomenon prevents the free motion of electrons. The resistance is known to be caused by the collision of free electron with atoms of the substance. Physicist George Simon Ohm suggest the law ohm that electric resistance is equal to voltage per ampere on pure metal. Hence, resistance is defined as the ratio of the applied voltage to the current through the substance. Most of metallic substance with rising temperatures the inter atomic vibrations increase and consequently offer more resistance to the movement of electrons causing the current. Thus, with increasing temperature the resistance of metallic substances increases. Refractory metals are a class of metals that are extraordinarily resistant to heat. The well-known Na-AMTEC is working between 800 K to 1300 K. Most of materials does not meet the criteria of aforementioned working condition in sense of thermo-condition except the five elements two of fifth period (niobium and molybdenum) and three of the sixth period (tantalum, tungsten and rhenium). They all share some properties, including a melting point above 2,200 K and high hardness at room temperature, except ductile transition character of niobium. Pure niobium has a Mohs hardness rating similar to that of pure titanium. Hence, the selection of candidate materials for Na-AMTEC as electrical electrode, current collector and lead is narrowed down to the minimum requirement of temperature resistance and electrical conductivity. In case of electrical resistance of Na-AMTEC is derived as following that the total resistance, R_T of Na-AMTEC is sum of the following resistances R_B (Resistance of Beta-Alumina Solid Electrolyte, BASE) + R_S (sheet resistance) + R_C (contact resistance) + R_L (lead resistance). Mostly, the sum of the rest of resistances is larger than the resistance of BASE. ● Correlation of Voltage, Ampere and Resistance: V ∝ I , V = RI , R= V/I ● Total electrical resistance of Na-AMTEC: R_T = R_B + R_S + R_C + R_L, R_B < R_S + R_C + R_L ● Correlation of resistances of Na-AMTEC: R_T ∝ 2 R_B Nonetheless, there is a reliability issue when measuring the electrical resistance which is intricate compared to the concept of electrical conductivity measurement on room temperature by virtue of the continuous temperature deviation during the Na-AMTEC cell test under elevated temperature. This study is to report the effort to develop the methodology of measurement reliability of the electrical resistance under high temperature state.