• Journal of the Korea Society for Simulation
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• v.18 no.3
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• pp.83-90
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• 2009

Since wireless sensor networks are deployed in open environments, an attacker can physically capture some sensor nodes. Using information of compromised nodes, an attacker can launch false data injection attacks that report nonexistent events. False data can cause false alarms and draining the limited energy resources of the forwarding nodes. In order to detect and discard such false data during the forwarding process, various security solutions have been proposed. But since they are prevention-based solutions that involve additional operations, they would be energy-inefficient if the corresponding attacks are not launched. In this paper, we propose a detection method that can detect false data injection attacks without extra overheads. The proposed method is designed based on the signature of false data injection attacks that has been derived through simulation. The proposed method detects the attacks based on the number of reporting nodes, the correctness of the reports, and the variation in the number of the nodes for each event. We show the proposed method can detect a large portion of attacks through simulation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.447-448
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• 2021

The boundary-based security architecture has the advantage of easy deployment of security solutions and high operational efficiency. The boundary-based security architecture is easy to detect and block externally occurring security threats, but is inappropriate to block internally occurring security threats. Unfortunately, internal security threats are increasing in frequency. In order to solve this problem, a zero trust model has been proposed. The zero trust model requires a real-time monitoring function to analyze the behavior of a subject accessing various information resources. However, there is a limit to real-time monitoring of file access of a subject confirmed to be trusted in the system. Accordingly, this study proposes a method to monitor user's file access in real time. To verify the effectiveness of the proposed monitoring method, the target function was verified after the demonstration implementation. As a result, it was confirmed that the method proposed in this study can monitor access to files in real time.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.3
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• pp.173-179
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• 2014

This is an experimental study for recycling coal ash left over from coal use as a potential fine aggregate in concrete. Coal ash is generally divided into either fly ash or bottom ash. Fly ash has been utilized as a substitution material for cement in concrete mixes. On the other hand, bottom ash has the problem of low recycling rates, and thus it has been primarily reclaimed. This study partially substituted fine concrete aggregates with bottom ash to increase its application rate and therefore its recycling rate; its suitability for this purpose was confirmed. The concrete's workability dropped noticeably with increasing bottom ash content when a fixed water-cement ratio of concrete mix was used. Thus, concrete mixes with higher ratio levels are required. To address this problem, concrete was mixed using a polycarboxylate high-range water reducing agent. The fluidity and air entrainment immediately after mixing the concrete and 1 h after mixing were measured, thereby replicating the time concrete is placed in the field when produced either in a ready-mixed concrete or in a batch plant. As a result of this research, the workability and air entrainment were maintained 1 h after mixing for a concrete mixture with approximately 30% of its fine concrete aggregates substituted with the bottom ash. A slight drop in compression strength was seen; however, this confirmed that potential of using bottom ash as a fine aggregate in concrete.

• Journal of Technologic Dentistry
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• v.17 no.1
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• pp.82-108
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• 1995

인력은 한 사회에 있어서 자본을 축적하며 자연자원을 개발하고 사회 경제 정치적 조직을 성장시키는 변화요인으로, 인간을 중심으로 하는 사회경제적 자원을 종합적으로 지칭하는 말이다. 이렇게 국가 사회가 필요로 하는 인력을 정부가 적절히 계획하여, 형성시키며, 배분 및 활용하는 문제를 논리적이고 일관성 있게 다루는 것을 인력정책이라 한다. 이러한 거시적이고 대 사회적인 정부의 인력정책은 국민의 건강과 생명을 보호하기 위한 보건의료 서비스를 제공해야 하는 의료인력을 대상으로 하는 경우 그 중요성이 더욱 특별하다 할 것이다. 국민에 대한 보건의료 서비스는 훈련된 보건 인력에 의해서 제공되며, 국가의 인력정책의 결과로 나타나는 보건의료인력 공급의 적합성은 인력의 불균형이라는 개념들을 통해서 검토될 수 있다. 의료인력의 불균형이라 함은 의료인력의 수, 종류, 기능, 분포, 질 등과 의료서비스에 대한 국민의 전체적 요구에 대응하여 정부가 생산하여 채용, 지원, 유시할 수 있는 정부 능력의 한계를 의미한다. 다시 말해서 국민에 대한 의료서비스의 적정화는 잘 훈련된(well qualified) 의료인력이 충분히 공급되어야(adequately supplied) 하고, 또한 적절히 분포되어야(well distributed) 한다는 양적, 질적, 그리고 분포의 세 가지 측면에서 살펴볼 수 있다. 질적, 양적, 그리고 분포의 불균형이라는 범주를 통하여 살펴본 치과기공사 분야의 인력정책에 대한 연구 결과와 개선방안은 다음과 같다. 첫째, 수적 불균형의 면에서 치과기공사의 인력은 1970년대 중반이래 계속 과잉 공급되어 왔으며, 이에 대해 정부는 그동안 소극적으로 대처하므로 과잉공급을 가속시켜왔다. 따라서 이러한 과잉공급을 최소하기 위해서는 치과이용에 대한 수요의 확장, 무면허자의 취업규제단속 및 대학의 치과기공학과 정원 축소 등을 생각해 볼 수 있다. 이러한 외형상의 과잉공급에도 불구하고 현업에 종사하는 실제인력은 수용에 비해 부족한 과소 공급현상을 빚고 있다는 점이 문제이다. 이러한 역설적인 현상을 타파하기 위하여 무면허자의 적발을 위시한 제도적 장치가 마련되어야 한다. 둘째, 질적 불균형은 수적 과잉공급에 의한 취업률 저하로 인한 실력 있는 전문인력 확보의 어려움과 전문 교육인력 및 교육시설의 열악한 조건이 원인으로 지적될 수 있으며, 이에 대한 해결방안으로 적절한 인력수요의 조절과 교육인력 및 시설 여건의 향상이 요망된다. 예컨대 3년제로 되어있는 학제를 4년제로 상향조정하는 방안을 고려할 수 있다. 세째, 치과기공사 분야의 인력분포 불균형은 그다지 심각하지는 않은 것으로 나타난다. 그러나 변화하는 소득수준과 사회환경은 의료인력과 균등한 지역적 분포에 대해 지속적인 관심을 가질것을 요청한다고 할 것이다. 이를 위하여 현재의 공중보건의 제도처럼 치기공 분야의 인력을 무의촌지역에 배치하여 공익요원으로 봉사케 하는 제도를 생각해 볼 수 있다.

• Economic and Environmental Geology
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• v.35 no.6
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• pp.545-552
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• 2002

In order to investigate the influence of nuclear power plant operation on its nearby environment, soil, stream and marine sediment samples were collected in the vicinity of the Youngkwang Nuclear Power Plant in Korea, and analyzed for artificial and natural radionuclide radioactivity. From the analytical result, Cs-137 was detected in most soil samples. but it may have been derived fiom past nuclear weapon tests because Cs-134 having short half-live was not detected. The radioactivities of Cs-137 in the sediment samples were also detected which are within the normal range in the sediments based upon the published literature between 1997 and 1999. For the quality control of radioactivity analysis of environmental samples, sets of marine sediments in the Gamami area were analyzed using two HPGe Gamma-ray Spectroscopes (30% and 45%) according to the geostatistical sampling strategy, and Cs-137 and K-40 results were interpreted by analysis of variance (ANOVA). In the two-way ANOVA, variances derived from the geochemical variation were significant, but errors from sampling and analytical procedures are negligible. In conclusion. all the radioanalytical procedures of this study including sampling are validated to be acceptable.

• Korean Journal of Plant Resources
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• v.8 no.2
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• pp.209-215
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• 1995

This experiment was carried out to elucidate the effect of row width and hill space on growth and yield in cynanchum wilfordii on experimental fields of chungbuk Provincial Rural Development Administration. Emergence date was May 25 and had no differences between planting density. Vine length was 219cm with row 40cm, 220cm, with 50cm and 225cm with 60cm, and in hill spaces, it was 225cm with hill space 10cm, 219cm with 15cm, and 218cm with 20cm. No. of leaves was same tendencies to vine length and was more increased as the hill space was narrower. Root length was longer about 0.9cm to 1.4cm as the hill space was wider, and no. of root had no difference between planting tensity. Yield was more increased row width was wider and was decreased hill space was wider. And the profitalble planting density was row width 50cm and hill space 10cm in the cultivation cynanchum wilfordii.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.3
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• pp.282-289
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• 2017

The flexural behavior tests of UHPC segmental Box girder which has 160MPa compressive strength and 15.4m length were carried out. The test variables are area of prestressing wires, volume fraction of steel fibers and longitudinal reinforcing bars in upper flange and web. PS tendons which has 32 strands of 15.2mm diameter in lower flange, 24 strands and 14 strands in lower flange were arranged and volume fraction of 2%, 1.5% and 1.0% is used in box girder concrete. UHPFRC box girder which has 32 strands in lower flange showed the over reinforcement and brittle behavior. UHPFRC box girder which has 24 strands showed the similar peak load as 32 strands girder and ductile behavior as large deflection. UHPFRC box girder which has 14 strands showed half of the peak load of 24 strands box girder and ductile behavior. After the application of the formular for the reinforcement index to the behavior of the UHPFRC box girders, reinforcement index does not determine the characteristic of behavior of UHPFRC box girder exactly. So the index should consider the dimension precisely and modify the reference value corresponding to the 0.005 strain of the prestressing strands.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.3
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• pp.290-297
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• 2017

The flexural behavior tests of UHPC segmental U-girder and composite U-girder which has 160MPa compressive strength and 15.4m length were carried out. The test variables are volume fraction of steel fibers and slab over the U-girder. Each U-girder has longitudinal re-bars in web and lower flange. PS tendons which has 2 of 15.2mm diameter in upper flange and PS tendons which has 7 of 15.2mm diameter in lower flange were arranged and prestressed at onetime in U-girder connection stage. Enough strong prestressing force which applied to U-girder due to ultra high performance concrete strength can withstand the self weight and dead load in U-girder stage. By comparison with the brittle behavior of U-girder, composite U-girder showed the stable and ductile behavior. After the construction of slab over U-girder, flexural load capacity of composite U-girder can bear the design load in final construction stage with only one time prestressing operation which already carried out in U-girder stage. This simple prestressing method due to the ultra high strength concrete have the advantage in construction step and cost. The shear key which has narrow space has the strong composite connection between ultra high strength concrete U-girder and high strength concrete slab didn't show any slip and opening right before failure load.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.62-62
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• 2018

산꼬리풀(Veronica rotunda var. subintegra T.Yamaz.)은 다년생 초본류로 달성이라는 꽃말을 가진 우리나라에만 자생하는 특산식물이다. 줄기는 곧게 서며, 줄기 끝에 보라색의 꽃이 총상화서로 피어 관상가치도 우수하다. 또한, 전초를 일지향이라 불리우며, 중약대사전에는 천식과 기침, 감기, 기관지염 등에 효능이 있다고 보고되었다. 이러한 산꼬리풀의 육묘 체계의 확립을 위하여 2017년 6월 2일부터 7월 31일까지 약 8주간 육묘하였다. 종자 육묘기술 개발을 위한 공통조건은 200구 트레이에 원예상토를 충진한 다음 셀 당 4립씩 파종하여 55% 차광막이 설치된 배드에 배치하였으며, 이후 4, 6주차에 Hyponex $500mg{\cdot}L^{-1}$을 처리하였다. 토양실험은 원예상토 단용[$300-200-200mg{\cdot}L^{-1}$(N-P-K)], 피트모스:펄라이트(3:1) 및 코코피트:펄라이트(3:1) 혼용토를 사용하였다. 피트모스와 코코피트의 혼용토는 원예상토의 비료농도를 기준으로 0-0-0, 300-200-200, $600-400-400mg{\cdot}L^{-1}$의 비료를 첨가하였다. 파종 립수별 실험은 셀탕 1, 2, 4 및 6립으로 하였으며, 추비는 hyponex(6.5-6-19) 0, 500, $1000mg{\cdot}L^{-1}$를 증류수에 희석하여 2회 분무기로 살포하였다. 차광 실험은 0, 55, 75% 등의 차광막이 설치된 곳에서 수행하였다. 연구의 결과, 산꼬리풀의 육묘는 원예상토를 사용하는 것이 다른 토양에 비해 우수한 결과를 보였다. 초장, 경직경 및 엽수는 원예상토를 이용하는 것이 가장 효과적이었으며, 다음으로 피트모스:펄라이트 혼용토 순이었다. 근장의 경우, 피트모스 혼용토에서 비료 농도와 관계없이 원예상토에 비해 유의적으로 길었다. 파종립수에 따른 초장과 경직경은 1, 2립 파종구에서 가장 양호하였으며, 파종량이 적을수록 길고 굵어지는 경향이었다. 엽수도 셀 당 파종량이 적을수록 많아지는 경향이었으나, 유의적인 큰 차이는 확인되지 않았다. 추비는 지상부의 경우 hyponex $500mg{\cdot}L^{-1}$ 처리 시 생육의 증가 효과가 있었지만, 비교적 고농도인 $1000mg{\cdot}L^{-1}$ 처리구에서는 생육에 효과가 없거나 억제되는 결과를 보였다. 한편, 근장은 처리농도가 높을수록 증가하는 경향이었고, hyponex $1000mg{\cdot}L^{-1}$ 처리구(9.9 cm)에서 가장 길었다. 산꼬리풀의 유묘 재배 시 차광처리는 경직경과 근장을 감소시키는 결과를 보였으며, 초장과 엽수는 처리에 따른 유의적인 차이는 없었다.

• Journal of dental hygiene science
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• v.16 no.4
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• pp.263-271
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• 2016

This study aimed at comprehending the duty, role, and difficulty of intermediary manager through in-depth investigation of dental hygienist intermediary managers experienced over 10 years working in a dental clinic. In-depth interviews were conducted with 10 dental intermediary managers and Giorgi's analysis method was used to analyze the data. Findings revealed that the work experience of the dental hygienist intermediary managers appeared in the range of "becoming an intermediary manager through various processes", "various duties that they experience as an intermediary manager", "difficulty as an intermediary manager", "ability that they perceive as necessary for being a dental intermediary manager", and "worthiness they feel as the intermediary manager". The dental intermediary managers complained of difficulties at work, and appeared to perform various tasks such as human resource management, clinic management support, and patient's management. Accordingly, the researcher considers that research on dental intermediary managers' capacity development necessary.