• Title/Summary/Keyword: Computation program

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Numerical Analysis of Steel-strengthened Concrete Panels Exposed to Effects of Blast Wave and Fragment Impact Load Using Multi-solver Coupling (폭풍파 및 파편 충돌에 대한 강판보강 콘크리트 패널의 복합적 수치해석)

  • Yun, Sung-Hwan;Park, Taehyo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.1A
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    • pp.25-33
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    • 2011
  • The impact damage behavior of steel-strengthened concrete panels exposed to explosive loading is investigated. Since real explosion experiments require the vast costs to facilities as well as the blast and impact damage mechanisms are too complicated, numerical analysis has lately become a subject of special attention. However, for engineering problems involving blast wave and fragment impact, there is no single numerical method that is appropriate to the various problems. In order to evaluate the retrofit performance of a steel-strengthened concrete panel subject to blast wave and fragment impact loading, an explicit analysis program, AUTODYN is used in this work. The multi-solver coupling methods such as Euler-Lagrange and SPH-Lagrange coupling method in order to improve efficiency and accuracy of numerical analysis is implemented. The simplified and idealized two dimensional and axisymmetric models are used in order to obtain a reasonable computation running time. As a result of the analysis, concrete panels subject to either blast wave or fragment impact loading without the steel plate are shown the scabbing and perforation. The perforation can be prevented by concrete panels reinforced with steel plate. The numerical results show good agreement with the results of the experiments.

Measurement of Classes Complexity in the Object-Oriented Analysis Phase (객체지향 분석 단계에서의 클래스 복잡도 측정)

  • Kim, Yu-Kyung;Park, Jai-Nyun
    • Journal of KIISE:Software and Applications
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    • v.28 no.10
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    • pp.720-731
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    • 2001
  • Complexity metrics have been developed for the structured paradigm of software development are not suitable for use with the object-oriented(OO) paradigm, because they do not support key object-oriented concepts such as inheritance, polymorphism. message passing and encapsulation. There are many researches on OO software metrics such as program complexity or design metrics. But metrics measuring the complexity of classes at the OO analysis phase are needed because they provide earlier feedback to the development project. and earlier feedback means more effective developing and less costly maintenance. In this paper, we propose the new metrics to measure the complexity of analysis classes which draw out in the analysis based on RUP(Rational Unified Process). By the collaboration complexity, is denoted by CC, we mean the maximum number of the collaborations can be achieved with each of the collaborator and determine the potential complexity. And the interface complexity, is denoted by IC, shows the difficulty related to understand the interface of collaborators each other. We verify theoretically the suggested metrics for Weyuker's nine properties. Moreover, we show the computation results for analysis classes of the system which automatically respond to questions of the user using the text mining technique. As a result of the comparison of CC and CBO and WMC suggested by Chidamber and Kemerer, the class that have highly the proposed metric value maintain the high complexity at the design phase too. And the complexity can be represented by CC and IC more than CBO and WMC. We can expect that our metrics may provide us the earlier feedback and hence possible to predict the efforts, costs and time required to remainder processes. As a result, we expect to develop the cost-effective OO software by reviewing the complexity of analysis classes in the first stage of SDLC(Software Development Life Cycle).

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A Study on Computation of the Reduction Rate in the Total Cost of Ownership of the Open Source Software in Comparison to the Commercial Software (상용소프트웨어대비 공개소프트웨어 총소유비용 절감비율 산정에 관한 연구)

  • Kim, Shin-Pyo;Kim, Tae-Yeol;Park, Keun-Ha
    • Journal of Digital Convergence
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    • v.11 no.3
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    • pp.115-126
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    • 2013
  • The purpose of this study was to confirm the extent of the reduction in the total cost of ownership of the open source software in comparison to the commercial software installed for information system, PC and cloud computing. Accordingly, the actual reduction rates in the total cost of ownership, when open source software is installed in the information system, PC and cloud computing, were computed and analyzed for 51 companies in the area of information system, 18 companies in the area of PC and 6 companies in the area of cloud computing, which included government institution, educational institution and private enterprises. The results of expert survey illustrated that the reduction rates are (1)63.3% on the average for the 4areas of information system, namely, DBMS, WAS, Web and OS, (2) 59.4% on the average for the 6 areas of PC, namely, OS, Documentation Program, Back-up and Restoration, Screen Capture, Vaccine and Others and (3) 61.2% on the average for the 6 areas of cloud computing, namely, Virtualization, OS, WEM/WAS, DBMS, DFS and Cloud Management.

Improvement of Address Pointer Assignment in DSP Code Generation (DSP용 코드 생성에서 주소 포인터 할당 성능 향상 기법)

  • Lee, Hee-Jin;Lee, Jong-Yeol
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.45 no.1
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    • pp.37-47
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    • 2008
  • Exploitation of address generation units which are typically provided in DSPs plays an important role in DSP code generation since that perform fast address computation in parallel to the central data path. Offset assignment is optimization of memory layout for program variables by taking advantage of the capabilities of address generation units, consists of memory layout generation and address pointer assignment steps. In this paper, we propose an effective address pointer assignment method to minimize the number of address calculation instructions in DSP code generation. The proposed approach reduces the time complexity of a conventional address pointer assignment algorithm with fixed memory layouts by using minimum cost-nodes breaking. In order to contract memory size and processing time, we employ a powerful pruning technique. Moreover our proposed approach improves the initial solution iteratively by changing the memory layout for each iteration because the memory layout affects the result of the address pointer assignment algorithm. We applied the proposed approach to about 3,000 sequences of the OffsetStone benchmarks to demonstrate the effectiveness of the our approach. Experimental results with benchmarks show an average improvement of 25.9% in the address codes over previous works.

A Comparative Study on Dietary Life according to the Obesity Assessment Methods of Higher Grade Elementary School Students in Jeonju (전주지역 고학년 초등학생의 비만판정 방법에 따른 식생활 비교연구)

  • Yu, Ok-Kyeong;Cha, Youn-Soo
    • Korean Journal of Human Ecology
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    • v.9 no.4
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    • pp.83-93
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    • 2006
  • This study was done for finding out if eating habits, eating behaviors were different between non-obese and obese elementary school students in Jeonju Area. Total 2568 students of 1364 male and 1204 female of the 4th, 5th, and 6th year in 5 elementary schools were surveyed and the statistics of the result was analyzed by SPSS program. The results are summarized as follows: 1. Obesity was defined as Body Mass Index(BMI) that exceeded 85th and Obesity Index(OI) that exceeded 110. First, subjects were divided into 4 groups : lean, normal, overweight and obese. Second subjects were reclassified into non-obese(lean and normal) and obese(overweight and obese) groups. Average height of male and female students were 142.5cm, 143.1cm and weight of those were 36.4kg and 37.9kg respectively. 2. As results of obesity computation, obese male students were 19.6%(overweight 11.3%, obese 8.3%) in BMI and obese male students were 25.0%(overweight 12.5.%, obese 12.5%) in OI. Especially Obesity percent rate of male student were significantly higher on that of female student in OI method. 3. Examining obesity between male and female, there were statistically different between male students and female students in OI, but there were not statistically different in BMI. With regard to grade level(4th, 5th, 6th), there were statistically different among grade levels. 4. Examining correlation between eating habits(eating behaviors) and obesity, there were statistically significant in some cases. For example, there were statistically significant correlation between fast eating habit and obesity. And the relation analysis of general environments and obesity showed that there were statistically significant in some cases. These results suggest that the number of overweight students can be increased due to the amount and kinds of food children have as well as the general causes of overweight such as genetic, environmental and psychological reason. Surveying about children's eating habits, eating behaviors this study methodically. Working with parents is necessary and comparison of eating habits, eating behaviors and nutrition knowledge between the past and their presents are also needed in a future.

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Analysis of Principal Stress Distribution Difference of Tensile Plate with Partial Through-hole (부분 관통 구멍이 있는 인장판의 주응력 분포 차이 해석)

  • Park, Sang Hyun;Kim, Young Chul;Kim, Myung Soo;Baek, Tae Hyun
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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    • v.7 no.2
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    • pp.437-444
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    • 2017
  • Stress concentrations around discontinuities, such as a hole in cross section of a structural member, have great importance because the most materials failure around the region may be occurred. Stress on the point applied by concentrated load reaches much larger value than the average stress in structural member. In this paper, stress analysis was performed for the plate with a partial through-hole to find the difference of the principal stress distribution. The difference between maximum principal stress and minimum principal stress in photoelasticity is equal to the value obtained by multiplying the isochromatic fringe order by the fringe constant of the material divided by the distance through which the light passes, that is, the thickness of the specimen. Since the difference of principal stress is proportional to the photoelastic fringe order, the distribution of the principal stress difference by the finite element analysis can be compared with the photoelasticity experimental result. ANSYS Workbench, that is the finite element software, is used to compute the differences of principal stresses at the specific points on the measured lines. The computation values obtained by ANSYS are compared with the experimental measurements by photoelasticity, and two results are comparable to each other. In addition, the stress concentration factor is obtained using the stress distribution analyzed from the variation of hole depth. Stress concentration factor is increasing, as the depth of hole increase.

Investigation on Characteristics of Swine Manure of Optimum Volume for Escalator Reversing Composting Facility (돼지분뇨 특성에 따른 기계교반 퇴비화시설의 적정용적 산정 연구)

  • Kwag, J.H.;Choi, D.Y.;Park, C.H.;Jeong, K.H.;Kim, J.H.;Yoo, Y.H.;Youn, C.K.;Ra, C.S.
    • Journal of Animal Environmental Science
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    • v.14 no.2
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    • pp.105-112
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    • 2008
  • This study was carried out to investigate evaporation rate of moisture per surface area and degradation rate of organic matter in full scale escalator reversing composting facility were analyzed to develope a computer program for the computation of an optimum volume of composting facility according to handling methods of swine farm, moisture levels of manure, degradation rate of organics and evaporation rate of moisture during composting. The obtained results can be followed as bellow; The temperature in full scale escalator reversing composting facility during composting reached $70^{\circ}C$ in 4 days and maintained until 11 days. Reduction rate of moisture and density was average 1.20% and 29.7%, respectively. Annual degradation rate of organic matter was 3.53%, showing lowest rate in winter as 3.23%. These seasonal degradation rate could be a factor to be considered for proper management and installation of composting facility. When computed with the amount of feces, urine, slurry and manure plus wastewater produced, the optimum volumes of composting facility for slurry and manure plus wastewater including each 95% moisture was $229m^3$ and $277m^3$, respectively, showing 21% ($48m^3$) difference.

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Koreanized Analysis System Development for Groundwater Flow Interpretation (지하수유동해석을 위한 한국형 분석시스템의 개발)

  • Choi, Yun-Yeong
    • Journal of the Korean Society of Hazard Mitigation
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    • v.3 no.3 s.10
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    • pp.151-163
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    • 2003
  • In this study, the algorithm of groundwater flow process was established for koreanized groundwater program development dealing with the geographic and geologic conditions of the aquifer have dynamic behaviour in groundwater flow system. All the input data settings of the 3-DFM model which is developed in this study are organized in Korean, and the model contains help function for each input data. Thus, it is designed to get detailed information about each input parameter when the mouse pointer is placed on the corresponding input parameter. This model also is designed to easily specify the geologic boundary condition for each stratum or initial head data in the work sheet. In addition, this model is designed to display boxes for input parameter writing for each analysis condition so that the setting for each parameter is not so complicated as existing MODFLOW is when steady and unsteady flow analysis are performed as well as the analysis for the characteristics of each stratum. Descriptions for input data are displayed on the right side of the window while the analysis results are displayed on the left side as well as the TXT file for this results is available to see. The model developed in this study is a numerical model using finite differential method, and the applicability of the model was examined by comparing and analyzing observed and simulated groundwater heads computed by the application of real recharge amount and the estimation of parameters. The 3-DFM model is applied in this study to Sehwa-ri, and Songdang-ri area, Jeju, Korea for analysis of groundwater flow system according to pumping, and obtained the results that the observed and computed groundwater head were almost in accordance with each other showing the range of 0.03 - 0.07 error percent. It is analyzed that the groundwater flow distributed evenly from Nopen-orum and Munseogi-orum to Wolang-bong, Yongnuni-orum, and Songja-bong through the computation of equipotentials and velocity vector using the analysis result of simulation which was performed before the pumping started in the study area. These analysis results show the accordance with MODFLOW's.

Conjunction Assessments of the Satellites Transported by KSLV-II and Preparation of the Countermeasure for Possible Events in Timeline (누리호 탑재 위성들의 충돌위험의 예측 및 향후 상황의 대응을 위한 분석)

  • Shawn Seunghwan Choi;Peter Joonghyung Ryu;John Kim;Lowell Kim;Chris Sheen;Yongil Kim;Jaejin Lee;Sunghwan Choi;Jae Wook Song;Hae-Dong Kim;Misoon Mah;Douglas Deok-Soo Kim
    • Journal of Space Technology and Applications
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    • v.3 no.2
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    • pp.118-143
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    • 2023
  • Space is becoming more commercialized. Despite of its delayed start-up, space activities in Korea are attracting more nation-wide supports from both investors and government. May 25, 2023, KSLV II, also called Nuri, successfully transported, and inserted seven satellites to a sun-synchronous orbit of 550 km altitude. However, Starlink has over 4,000 satellites around this altitude for its commercial activities. Hence, it is necessary for us to constantly monitor the collision risks of these satellites against resident space objects including Starlink. Here we report a quantitative research output regarding the conjunctions, particularly between the Nuri satellites and Starlink. Our calculation shows that, on average, three times everyday, the Nuri satellites encounter Starlink within 1 km distance with the probability of collision higher than 1.0E-5. A comparative study with KOMPSAT-5, also called Arirang-5, shows that its distance of closest approach distribution significantly differs from those of Nuri satellites. We also report a quantitative analysis of collision-avoiding maneuver cost of Starlink satellites and a strategy for Korea, being a delayed starter, to speed up to position itself in the space leading countries. We used the AstroOne program for analyses and compared its output with that of Socrates Plus of Celestrak. The two line element data was used for computation.

A Study on Hoslital Nurses' Preferred Duty Shift and Duty Hours (병원 간호사의 선호근무시간대에 관한 연구)

  • Lee, Gyeong-Sik;Jeong, Geum-Hui
    • The Korean Nurse
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    • v.36 no.1
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    • pp.77-96
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    • 1997
  • The duty shifts of hospital nurses not only affect nurses' physical and mental health but also present various personnel management problems which often result in high turnover rates. In this context a study was carried out from October to November 1995 for a period of two months to find out the status of hospital nurses' duty shift patterns, and preferred duty hours and fixed duty shifts. The study population was 867 RNs working in five general hospitals located in Seoul and its vicinity. The questionnaire developed by the writer was used for data collection. The response rate was 85.9 percent or 745 returns. The SAS program was used for data analysis with the computation of frequencies, percentages and Chi square test. The findings of the study are as follows: 1. General characteristics of the study population: 56 percent of respondents was (25 years group and 76.5 percent were "single": the predominant proportion of respondents was junior nursing college graduates(92.2%) and have less than 5 years nursing experience in hospitals(65.5%). For their future working plan in nursing profession, nearly 50% responded as uncertain The reasons given for their career plan was predominantly 'personal growth and development' rather than financial reasons. 2. The interval for rotations of duty stations was found to be mostly irregular(56.4%) while others reported as weekly(16.1%), monthly(12.9%), and fixed terms(4.6%). 3. The main problems related to duty shifts particularly the evening and night duty nurses reported were "not enough time for the family, " "afraid of security problems after the work when returning home late at night." and "lack of leisure time". "problems in physical and physiological adjustment." "problems in family life." "lack of time for interactions with fellow nurses" etc. 4. The forty percent of respondents reported to have '1-2 times' of duty shift rotations while all others reported that '0 time'. '2-3 times'. 'more than 3 times' etc. which suggest the irregularity in duty shift rotations. 5. The majority(62.8%) of study population found to favor the rotating system of duty stations. The reasons for favoring the rotation system were: the opportunity for "learning new things and personal development." "better human relations are possible. "better understanding in various duty stations." "changes in monotonous routine job" etc. The proportion of those disfavor the rotating 'system was 34.7 percent. giving the reasons of"it impedes development of specialization." "poor job performances." "stress factors" etc. Furthermore. respondents made the following comments in relation to the rotation of duty stations: the nurses should be given the opportunity to participate in the. decision making process: personal interest and aptitudes should be considered: regular intervals for the rotations or it should be planned in advance. etc. 6. For the future career plan. the older. married group with longer nursing experiences appeared to think the nursing as their lifetime career more likely than the younger. single group with shorter nursing experiences ($x^2=61.19.{\;}p=.000;{\;}x^2=41.55.{\;}p=.000$). The reason given for their future career plan regardless of length of future service, was predominantly "personal growth and development" rather than financial reasons. For further analysis, the group those with the shorter career plan appeared to claim "financial reasons" for their future career more readily than the group who consider the nursing job as their lifetime career$(x^2$= 11.73, p=.003) did. This finding suggests the need for careful .considerations in personnel management of nursing administration particularly when dealing with the nurses' career development. The majority of respondents preferred the fixed day shift. However, further analysis of those preferred evening shift by age and civil status, "< 25 years group"(15.1%) and "single group"(13.2) were more likely to favor the fixed evening shift than > 25 years(6.4%) and married(4.8%)groups. This differences were statistically significant ($x^2=14.54, {\;}p=.000;{\;}x^2=8.75, {\;}p=.003$). 7. A great majority of respondents(86.9% or n=647) found to prefer the day shifts. When the four different types of duty shifts(Types A. B. C, D) were presented, 55.0 percent of total respondents preferred the A type or the existing one followed by D type(22.7%). B type(12.4%) and C type(8.2%). 8. When the condition of monetary incentives for the evening(20% of salary) and night shifts(40% of. salary) of the existing duty type was presented. again the day shift appeared to be the most preferred one although the rate was slightly lower(66.4% against 86.9%). In the case of evening shift, with the same incentive, the preference rates for evening and night shifts increased from 11.0 to 22.4 percent and from 0.5 to 3.0 percent respectively. When the age variable was controlled. < 25 yrs group showed higher rates(31.6%. 4.8%) than those of > 25 yrs group(15.5%. 1.3%) respectively preferring the evening and night shifts(p=.000). The civil status also seemed to operate on the preferences of the duty shifts as the single group showed lower rate(69.0%) for day duty against 83. 6% of the married group. and higher rates for evening and night duties(27.2%. 15.1%) respectively against those of the married group(3.8%. 1.8%) while a higher proportion of the married group(83. 6%) preferred the day duties than the single group(69.0%). These differences were found to be statistically all significant(p=.001). 9. The findings on preferences of three different types of fixed duty hours namely, B, C. and D(with additional monetary incentives) are as follows in order of preference: B type(12hrs a day, 3days a wk): day shift(64.1%), evening shift(26.1%). night shift(6.5%) C type(12hrs a day. 4days a wk) : evening shift(49.2%). day shift(32.8%), night shift(11.5%) D type(10hrs a day. 4days a wk): showed the similar trend as B type. The findings of higher preferences on the evening and night duties when the incentives are given. as shown above, suggest the need for the introductions of different patterns of duty hours and incentive measures in order to overcome the difficulties in rostering the nursing duties. However, the interpretation of the above data, particularly the C type, needs cautions as the total number of respondents is very small(n=61). It requires further in-depth study. In conclusion. it seemed to suggest that the patterns of nurses duty hours and shifts in the most hospitals in the country have neither been tried for different duty types nor been flexible. The stereotype rostering system of three shifts and insensitiveness for personal life aspect of nurses seemed to be prevailing. This study seems to support that irregular and frequent rotations of duty shifts may be contributing factors for most nurses' maladjustment problems in physical and mental health. personal and family life which eventually may result in high turnover rates. In order to overcome the increasing problems in personnel management of hospital nurses particularly in rostering of evening and night duty shifts, which may related to eventual high turnover rates, the findings of this study strongly suggest the need for an introduction of new rostering systems including fixed duties and appropriate incentive measures for evenings and nights which the most nurses want to avoid, In considering the nursing care of inpatients is the round-the clock business. the practice of the nursing duty shift system is inevitable. In this context, based on the findings of this study. the following are recommended: 1. The further in-depth studies on duty shifts and hours need to be undertaken for the development of appropriate and effective rostering systems for hospital nurses. 2. An introduction of appropriate incentive measures for evening and night duty shifts along with organizational considerations such as the trials for preferred duty time bands, duty hours, and fixed duty shifts should be considered if good quality of care for the patients be maintained for the round the clock. This may require an initiation of systematic research and development activities in the field of hospital nursing administration as a part of permanent system in the hospital. 3. Planned and regular intervals, orientation and training, and professional and personal growth should be considered for the rotation of different duty stations or units. 4. In considering the higher degree of preferences in the duty type of "10hours a day, 4days a week" shown in this study, it would be worthwhile to undertake the R&D type studies in large hospital settings.

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