• Title/Summary/Keyword: Highly Efficient

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The Contact and Parallel Analysis of SPH Using Cartesian Coordinate Based Domain Decomposition Method (Cartesian 좌표기반 동적영역분할을 고려한 SPH의 충돌 및 병렬해석)

  • Moonho Tak
    • Journal of the Korean GEO-environmental Society
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    • v.25 no.4
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    • pp.13-20
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    • 2024
  • In this paper, a parallel analysis algorithm for Smoothed Particle Hydrodynamics (SPH), one of the numerical methods for fluidic materials, is introduced. SPH, which is a meshless method, can represent the behavior of a continuum using a particle-based approach, but it demands substantial computational resources. Therefore, parallel analysis algorithms are essential for SPH simulations. The domain decomposition algorithm, which divides the computational domain into partitions to be independently analyzed, is the most representative method among parallel analysis algorithms. In Discrete Element Method (DEM) and Molecular Dynamics (MD), the Cartesian coordinate-based domain decomposition method is popularly used because it offers advantages in quickly and conveniently accessing particle positions. However, in SPH, it is important to share particle information among partitioned domains because SPH particles are defined based on information from nearby particles within the smoothing length. Additionally, maintaining CPU load balance is crucial. In this study, a highly parallel efficient algorithm is proposed to dynamically minimize the size of orthogonal domain partitions to prevent excess CPU utilization. The efficiency of the proposed method was validated through numerical analysis models. The parallel efficiency of the proposed method is evaluated for up to 30 CPUs for fluidic models, achieving 90% parallel efficiency for up to 28 physical cores.

Review on hazardous microcystins originating from harmful cyanobacteria and corresponding eliminating methods (유해 남세균 유래 마이크로시스틴의 위해성과 제거 방안 고찰)

  • Sok Kim;Yoon-E Choi
    • Korean Journal of Environmental Biology
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    • v.41 no.4
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    • pp.370-385
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    • 2023
  • Cyanobacterial harmful algal blooms (Cyano-HABs) are an international environmental problem that negatively affects the ecosystem as well as the safety of water resources by discharging cyanotoxins. In particular, the discharge of microcystins (MCs), a highly toxic substance, has been studied most actively, and various water treatment methods have been proposed for this purpose. In this paper, we reviewed adsorption technology, which is recognized as the most feasible, economical, and efficient method among suggested treatment methods for removing MCs. Activated carbons (AC) are widely used adsorbents for MCs removal, and excellent MCs adsorption performance has been reported. Research on alternative adsorption materials for AC such as biochar and biosorbents has been conducted, however, their performance was lower compared to activated carbon. The impacts of adsorbent properties(characteristics of pore surface chemistry) and environmental factors (solution pH, temperature, natural organic matter, and ionic strength) on the MCs adsorption performance were also discussed. In addition, toward effective control of MCs, the possibility of the direct removal of harmful cyanobacteria as well as the removal of dissolved MCs using adsorption strategy was examined. However, to fully utilize the adsorption for the removal of MCs, the application and optimization under actual environmental conditions are still required, thereby meeting the environmental and economic standards. From this study, crucial insights could be provided for the development and selection of effective adsorbent and subsequent adsorption processes for the removal of MCs from water resources.

Evaluation of Viral Inactivation Efficacy of a Continuous Flow Ultraviolet-C Reactor (UVivatec) (연속 유동 Ultraviolet-C 반응기(UVivatec)의 바이러스 불활화 효과 평가)

  • Bae, Jung-Eun;Jeong, Eun-Kyo;Lee, Jae-Il;Lee, Jeong-Im;Kim, In-Seop;Kim, Jong-Su
    • Microbiology and Biotechnology Letters
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    • v.37 no.4
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    • pp.377-382
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    • 2009
  • Viral safety is an important prerequisite for clinical preparations of all biopharmaceuticals derived from plasma, cell lines, or tissues of human or animal origin. To ensure the safety, implementation of multiple viral clearance (inactivation and/or removal) steps has been highly recommended for manufacturing of biopharmaceuticals. Of the possible viral clearance strategies, Ultraviolet-C (UVC) irradiation has been known as an effective viral inactivating method. However it has been dismissed by biopharmaceutical industry as a result of the potential for protein damage and the difficulty in delivering uniform doses. Recently a continuous flow UVC reactor (UVivatec) was developed to provide highly efficient mixing and maximize virus exposure to the UV light. In order to investigate the effectiveness of UVivatec to inactivate viruses without causing significant protein damage, the feasibility of the UVC irradiation process was studied with a commercial therapeutic protein. Recovery yield in the optimized condition of $3,000\;J/m^2$ irradiation was more than 98%. The efficacy and robustness of the UVC reactor was evaluated with regard to the inactivation of human immunodeficiency virus (HIV), hepatitis A virus (HAV), bovine herpes virus (BHV), bovine viral diarrhea virus (BVDV), porcine parvovirus (PPV), bovine parvovirus (BPV), minute virus of mice (MVM), reovirus type 3 (REO), and bovine parainfluenza virus type 3 (BPIV). Non enveloped viruses (HAV, PPV, BPV, MVM, and REO) were completely inactivated to undetectable levels by $3,000\;J/m^2$ irradiation. Enveloped viruses such as HIV, BVDV, and BPIV were completely inactivated to undetectable levels. However BHV was incompletely inactivated with slight residual infectivity remaining even after $3,000\;J/m^2$ irradiation. The log reduction factors achieved by UVC irradiation were ${\geq}3.89$ for HIV, ${\geq}5.27$ for HAV, 5.29 for BHV, ${\geq}5.96$ for BVDV, ${\geq}4.37$ for PPV, ${\geq}3.55$ for BPV, ${\geq}3.51$ for MVM, ${\geq}4.20$ for REO, and ${\geq}4.15$ for BPIV. These results indicate that UVC irradiation using UVivatec was very effective and robust in inactivating all the viruses tested.

The Organization Commitment and Perception of Human Resource Management by Employment Types of School Foodservice Employees (학교급식 직원의 고용유형에 따른 인적 자원 관리 활동에 대한 인식과 조직 몰입도)

  • Lee, Ok;Cho, Minju;Chang, Hyeja
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.43 no.1
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    • pp.162-171
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    • 2014
  • As the foodservice industry is labor intensive, the efficient management of human resources is an essential element for improving operational efficiency. This study was designed to investigate the performance level of human resource management in self-operated school foodservices and to examine the relationship between human resource management, organizational commitment, and productivity. Whether these factors rated differently by employment and job types was also examined. Data were collected through questionnaires distributed to 60 dieticians and 240 cooks in Seongnam and Yongin. Frequency analysis, factor analysis, the t-test and multiple regression analysis were tested using Minitab. Human resource management practices rated highly in the dimension of employee training (3.51), followed by working environment (3.39), and turnover management (3.37). In contrast, reward management (1.73) and working condition (1.56) received the lowest score. Organizational commitment scored 3.65 points, and showed that dedication (3.82) was the highest score; however, self-esteem (3.50) was the lowest score. For human resource management, there were significant differences between employment types as full time workers (3.85) rated management more highly than part-time worker (3.43). Overall productivity was fairly high, especially in high school foodservices. Only the performance appraisal had an influence on organizational commitment (${\beta}$=0.292, P<0.05). Productivity was positively correlated with human resource management (r=0.432, P<0.001) and organizational commitment (r=0.36, P<0.01). In conclusion, school foodservices need to establish objective performance standards, and increase employee morale by enhancing reward systems and working conditions. In particular, irregular employees require training with job performance standards and given a proper reward program, depending on their performance, to improve organizational commitment.

The Limitation of Air Carriers' Cargo and Baggage Liability in International Aviation Law: With Reference to the U.S. Courts' Decisions (국제항공법상 화물.수하물에 대한 운송인의 책임상한제도 - 미국의 판례 분석을 중심으로 -)

  • Moon, Joon-Jo
    • The Korean Journal of Air & Space Law and Policy
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    • v.22 no.2
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    • pp.109-133
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    • 2007
  • The legal labyrinth through which we have just walked is one in which even a highly proficient lawyer could easily become lost. Warsaw Convention's original objective of uniformity of private international aviation liability law has been eroded as the world community ha attempted again to address perceived problems. Efforts to create simplicity and certainty of recovery actually may have created less of both. In any particular case, the issue of which international convention, intercarrier agreement or national law to apply will likely be inconsistent with other decisions. The law has evolved faster for some nations, and slower for others. Under the Warsaw Convention of 1929, strict liability is imposed on the air carrier for damage, loss, or destruction of cargo, luggage, or goods sustained either: (1) during carriage in air, which is comprised of the period during which cargo is 'in charge of the carrier (a) within an aerodrome, (b) on board the aircraft, or (c) in any place if the aircraft lands outside an aerodrome; or (2) as a result of delay. By 2007, 151 nations had ratified the original Warsaw Convention, 136 nations had ratified the Hague Protocol, 84 had ratified the Guadalajara Protocol, and 53 nations had ratified Montreal Protocol No.4, all of which have entered into force. In November 2003, the Montreal Convention of 1999 entered into force. Several airlines have embraced the Montreal Agreement or the IATA Intercarrier Agreements. Only seven nations had ratified the moribund Guatemala City Protocol. Meanwhile, the highly influential U.S. Second Circuit has rendered an opinion that no treaty on the subject was in force at all unless both affected nations had ratified the identical convention, leaving some cases to fall between the cracks into the arena of common law. Moreover, in the United States, a surface transportation movement prior or subsequent to the air movement may, depending upon the facts, be subject to Warsaw, or to common law. At present, International private air law regime can be described as a "situation of utter chaos" in which "even legal advisers and judges are confused." The net result of this barnacle-like layering of international and domestic rules, standards, agreements, and criteria in the elimination of legal simplicity and the substitution in its stead of complexity and commercial uncertainty, which manifestly can not inure to the efficient and economical flow of world trade. All this makes a strong case for universal ratification of the Montreal Convention, which will supersede the Warsaw Convention and its various reformulations. Now that the Montreal Convention has entered into force, the insurance community may press the airlines to embrace it, which in turn may encourage the world's governments to ratify it. Under the Montreal Convention, the common law defence is available to the carrier even when it was not the sole cause of the loss or damage, again making way for the application of comparative fault principle. Hopefully, the recent entry into force of the Montreal Convention of 1999 will re-establish the international legal uniformity the Warsaw Convention of 1929 sought to achieve, though far a transitional period at least, the courts of different nations will be applying different legal regimes.

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A Study on a Method to Use Activation and Awareness on Archives of University Student (대학생의 기록관 인식현황 및 이용 활성화 방안 연구)

  • Lee, Jung-eun;Gang, Juyeon;Kim, Eun-Sil;Kim, Yong
    • The Korean Journal of Archival Studies
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    • no.51
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    • pp.133-173
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    • 2017
  • The records and archives center provide a variety of archival information services in an effort to get closer to the public. However, there are still some problems with regard to the lack of awareness of records and archives. In order to activate the use of archives, it is necessary to understand the users of archives. Given the problems, this study aims to investigate the awareness of records and archives in university students who are potential users of archives as well as to suggest methods to activate the use of records and archives reflecting the characteristics of university students' awareness. As such, this study surveyed 182 university students at J university. The questionnaire items referred to Market & Opinion Research International (MORI) (2003) as a part of the projects conducted by the Museums Libraries Archives Council (MLA) and Cho's study (2008). The questionnaire items consisted of four major areas: awareness of records and archives, experience with records and archives or reasons of not using them, requirements for the use of archives by potential users, and efficient method of promoting archives. As a result of the survey, most of the university students are indifferent to records. However, they recognized that it is highly important to manage records that are related to historical values and archives that are relevant to information values. In addition, they showed a positive intention to use the archives in the future; thus, it is highly likely for them to be converted into active users through appropriate services. Based on the results, this study proposed important considerations for activating the use of the archives to university students, and suggested methods to activate the archives in terms of user education, program development, and user segmentation.

Analysis of Monitoring Characteristics of Small Stream for TMDL (오염총량관리를 위한 소하천 모니터링 자료의 특성 분석)

  • Ha, Don-Woo;Park, Seung-Ho;Joo, Sungmin;Lee, Gi-Soon;Baek, Jong-Hun;Jung, Kang-Young;Lee, Youngjea;Kim, Kyunghyun;Kim, Young-Suk
    • Journal of the Korean Society for Environmental Technology
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    • v.19 no.6
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    • pp.503-513
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    • 2018
  • In order to continuous watershed management and improve water quality at Yeong-san river system, we analyzed and evaluated data on the monitoring of small stream in city and county boundaries within the watershed. In-period monitoring is estimated to be more frequent in the second quarter than the first quarter, so it should be considered when evaluating the target water quality by setting the target water quality. A small stream in the Yeong-san river system has higher concentration in the downstream area than the upstream area. As a result of calculating the load of the measuring point, Y.b B3(Pungyeongjeongcheon) and Y.b E1(Sampocheon) were high. The result of correlation analysis by monitoring point in order to evaluate the correlation between BOD and T-P items, BOD was highly correlated with COD and TOC, and was affected by emission of pollutants related to organic matter. T-P was highly correlated with SS and COD, and was affected by rainfall. This study will provide basic data and direction for designing efficient and scientific method for water quality management by analyzing accumulated water quality data by conducting long-term monitoring.

Efficient Culture Method for Early Passage hESCs after Thawing (초기 계대 인간 배아줄기세포의 해동 후 효율적인 배양 방법)

  • Baek, Jin-Ah;Kim, Hee-Sun;Seol, Hye-Won;Seo, Jin;Jung, Ju-Won;Yoon, Bo-Ae;Park, Yong-Bin;Oh, Sun-Kyung;Ku, Seung-Yup;Kim, Seok-Hyun;Choi, Young-Min;Moon, Shin-Yong
    • Clinical and Experimental Reproductive Medicine
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    • v.36 no.4
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    • pp.311-319
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    • 2009
  • Objective: Human embryonic stem cells (hESCs) have the capacity to differentiate into all of the cell types and therefore hold promise for cell therapeutic applications. In order to utilize this important potential of hESCs, enhancement of currently used technologies for handling and manipulating the cells is required. The cryopreservation of hESC colonies was successfully performed using the vitrification and slow freezing-rapid thawing method. However, most of the hESC colonies were showed extremely spontaneous differentiation after freezing and thawing. In this study, we were performed to rapidly collect of early passage hESCs, which was thawed and had high rate of spontaneously differentiation of SNUhES11 cell line. Methods: Four days after plating, partially spontaneously differentiated parts of hESC colony were cut off using finely drawn-out dissecting pipette, which is mechanical separation method. Results: After separating of spontaneously differentiated cells, we observed that removed parts were recovered by undifferentiated cells. Furthermore, mechanical separation method was more efficient for hESCs expansion after thawing when we repeated this method. The recovery rate after removing differentiated parts of hESC colonies were 55.0%, 74.5%, and 71.1% when we have applied this method to three passages. Conclusion: Mechanical separation method is highly effective for rapidly collecting and large volumes of undifferentiated cells after thawing of cryopreserved early passage hESCs.

Development of an Efficient Screening Method for Resistance of Chili Pepper Plants to Meloidogyne incognita (뿌리혹선충 Meloidogyne incognita에 대한 저항성 고추를 선발하기 위한 효율적인 검정법 확립)

  • Hwang, Sung Min;Jang, Kyoung Soo;Choi, Yong Ho;Choi, Gyung Ja
    • Horticultural Science & Technology
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    • v.34 no.2
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    • pp.282-293
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    • 2016
  • Root-knot nematodes (Meloidogyne spp.) are major plant pathogens that cause reductions in yield and quality of several solanaceous crops, including pepper (Capsicum spp.). These losses can be averted through planting of resistant cultivars. Plants are defined as resistant when they suppress nematode reproduction. In this study, the resistance degrees of 102 commercial cultivars of chili pepper (Capsicum annuum) to a root-knot nematode, Meloidogyne incognita, were evaluated by comparing the number of egg masses on their roots to those of 'PR huimangchan', a highly susceptible cultivar that exhibited the most egg masses of the chili pepper cultivars evaluated. Among these cultivars, forty-four (43.1%) showed resistance to M. incognita and eighteen (17.6%) were moderately resistant. The other cultivars (39.3%) were determined to be susceptible. For further study, six chili pepper cultivars (i.e., Gangryeokjosenggeon, Shinsegae, Muhanjilju, PR Bulrocho, PR Huimangchan, and Jjang) with different levels of resistance to the nematode were selected. Changes in resistance of the six cultivars under several conditions, such as inoculum concentration, plant growth stage, and cultivation period after transplanting were investigated. We found that an efficient screening method for resistance of chili pepper to M. incognita is to transplant the chili pepper seedlings 7 days before inoculation, to inoculate 28-day-old plants with M. incognita by loading 5,000 eggs per plant into the pot of soil, to cultivate the plants in a greenhouse ($25{\pm}5^{\circ}C$) for 45-60 days, to measure the number of egg masses on roots of the seedlings, and then to determine the resistance response of the plants by comparing the number of egg masses on the roots with a reference-susceptible cultivar 'PR huimangchan'.

A Study on the Efficient Measurement of Airborne Asbestos Concentrations at Demolition Sites of Asbestos Containing Buildings, etc. in Seoul (서울시내 석면함유 건축물 철거 현장 등에서의 효과적인 공기 중 석면농도 측정을 위한 연구)

  • Lee, Jinhyo;Lee, Suhyun;Kim, Jeongyeun;Kim, Jihui;Chung, Sooknye;Kim, Jina;Oh, Seokryul;Kim, Iksoo;Shin, Jinho;Eo, Soomi;Jung, Kweon;Lee, Jinsook
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.24 no.2
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    • pp.113-121
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    • 2014
  • Objectives: This study is intended to seek credible and efficient measurements on airborne asbestos concentrations that allow immediate action by establishing complementary data through comparative analysis with existing PCM and KF-100 method real-time monitoring equipment in working areas in Seoul where asbestos-containing buildings are being demolished, including living environment surroundings. Materials: We measured airborne asbestos concentrations using PCM and KF-100 at research institutes, monitoring networks, subway stations and demolition sites of asbestos-containing buildings. Through this measurement data and KF-100 performance testing, we drew a conversion factor and applied it via KF-100. Finally we verified the relationship between PCM and KF-100 with statistical methods. Results: The airborne asbestos concentrations by PCM for the objects of study were less than the detection limit(7 fiber/$mm^2$) in three (20%) out of 15 samples. The highest concentration was 0.009 f/cc. The airborne asbestos concentrations by PCM in laboratories, monitoring networks, subway stations and demolition sites of asbestos-containing buildings were respectively $0.002{\pm}0.000$ f/cc, $0.004{\pm}0.001$ f/cc, $0.009{\pm}0.001$ f/cc, and $0.002{\pm}0.000$ f/cc. As a result of KF-100 performance testson rooftops, the conversion factor was 0.1958. Applying the conversion factor to KF-100 for laboratories, the airborne asbestos concentrations ratio of the two ways was nearly 1:1.5($R^2$=0.8852). Also,the airborne asbestos concentration ratio of the two ways was nearly 1:1($R^2$=0.9071) for monitoring networks, subway stations, and demolition sites of asbestos-containing buildings. As a result of independent sample t-tests, there was no distinction between airborne asbestos concentrations monitored in the two ways. Conclusions: In working areas where asbestos-containing buildings are being demolished, including living environment surroundings, quickly and accurately monitoring airborne asbestos scattered in the air around the working area is highly important. For this, we believea mutual interface of existing PCM and a real-time monitoring equipment method is possible.