• 터널과지하공간
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• 제22권2호
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• pp.86-92
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• 2012

점추정법은 exact probabilistic method로 간주되는 Monte Carlo simulation에 비해 계산의 정확도는 다소 떨어지지만, 성능함수의 통계 모멘트를 분석하기 위한 샘플링 수를 크게 줄일 수 있는 해석 과정에서의 간편함과 비교적 정확한 통계 모멘트의 계산으로 인해 지반 및 암반공학에서의 확률론적 신뢰성 평가에 자주 사용되고 있다. 본 연구에서는 Rosenblueth와 Zhou & Nowak의 점추정법과 Monte Carlo simulation의 계산 결과를 비교 분석하여 점추정법의 정확도와 적용성을 조사하였다. 비교 분석은 해석적 해가 주어진 탄성 지반내 원형터널의 라이닝 지보 문제를 대상으로 하였다. 분석 결과, 해석적 해가 비선형 함수임에도 불구하고, 점추정법과 Monte Carlo simulation에 의해 계산된 통계 모멘트가 평균 약 1-2%의 오차를 보여 수치해석과 연계한 지하구조물의 확률론적 신뢰성 평가를 위한 점추정법의 적용성을 확인하였다.

• 한국시뮬레이션학회논문지
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• 제16권4호
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• pp.43-55
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• 2007

생산 공정 제어방법들 중에서 이동평균 제어와 지수가중치 이동평균 제어는 가장 널리 사용되는 제어이다. 두 제어는 모두 정확한 제어식을 알고 있다는 전제 하에 최적화된 제어들이다. 이 논문에서는 제어식의 잘못된 예측으로부터 발생하는 문제점에 대해 다루었다. 추정한 모수의 정확도와 가중치 $\lambda$의 범위에 의해 결정되는 각각의 제어방식의 제어한계에 대해서 확인하고 제어 간의 성능을 평가하였다. 또한 잘못 추정된 모델이 존재하는 공정에서 Shift가 발생하였을 때 최적의 제어와 그것을 실제 공정에서 어떻게 적용할지에 대해서 연구하였다. 시뮬레이션을 통해 제안하는 방법의 효용성을 검증하였다.

• 한국축산시설환경학회지
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• 제21권1호
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• pp.9-20
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• 2015

The livestock manure recycling have been performed worldwide because of its environmental and economic benefits. However, domestic standard protocol was nothing for high solid manure. Therefore, This paper was conducted to review database configuration of manure characteristics, analysis methods, bio-methane potential test for high solid manure recycling. In American society of agricultural engineers standard, manure characteristics indicated about sort of thirty types. This is important information to determine for manure recycling method. Furthermore, in order to determine exact manure characteristics recommended that synchronized chemical analysis method among studies. Bio-methane potential tests are widely performed in studies about estimation of organic substrates methane production. Although various methods and parameters were used, was no standard protocol and guideline in domestic. Bio-methane potential test methods and parameters were reviewed through various researches. Consequently, this paper is expected that assist to additional studies and manure characteristic database.

• 대한치과보철학회지
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• 제39권6호
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• pp.633-640
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• 2001

Statement of problem. Relatively low success rate of root analogue implant system was supposed to be due to the time duration between extraction and implant installation. The use of three-dimensional computer tomography and the reconstruction of objects using rapid prototyping methods would be helpful to shorten this time. Purpose. This aim of this study was to evaluate the application possibility of the 3-dimensional computer tomography and the rapid prototyping to root analogue implants. Material and methods. Ten single rooted teeth were prepared. Width and height of the teeth were measured by the marking points. This was followed by CT scanning, data conversion and rapid prototyping model fabrication. 2 methods were used; fused deposition modelling and stereolithography. Same width and height of this models were measured and compared to the original tooth. Results. Fused deposition modelling showed an enlarged width and reduced height. The stereolithography showed more exact data compared with the fused deposition modelling. Smaller standard deviation were recorded in the stereolithographic method. Overall width error from tooth to rapid prototyping was 7.15% in fused deposition modelling and 0.2% in stereolithography. Overall height showed the tendency of reducing dimensions. Conclusion. From the results of this study, stereolithography seems to be very predictable method of fabricating root analogue implant.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권11호
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• pp.5671-5693
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• 2017

With the rapid development of cloud computing, more and more data owners are motivated to outsource their data to cloud for various benefits. Due to serious privacy concerns, sensitive data should be encrypted before being outsourced to the cloud. However, this results that effective data utilization becomes a very challenging task, such as keyword search over ciphertexts. Although many searchable encryption methods have been proposed, they only support exact keyword search. Thus, misspelled keywords in the query will result in wrong or no matching. Very recently, a few methods extends the search capability to fuzzy keyword search. Some of them may result in inaccurate search results. The other methods need very large indexes which inevitably lead to low search efficiency. Additionally, the above fuzzy keyword search methods do not support access control. In our paper, we propose a searchable encryption method which achieves fuzzy search and access control through algorithm design and Ciphertext-Policy Attribute-based Encryption (CP-ABE). In our method, the index is small and the search results are accurate. We present word pattern which can be used to balance the search efficiency and privacy. Finally, we conduct extensive experiments and analyze the security of the proposed method.

• 한국군사과학기술학회지
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• 제13권5호
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• pp.875-885
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• 2010

Recently, the role of Ubiquitous Sensor Network(USN) has been considered to be essential for supporting the near future Network Centric Warfare(NCW) and Tactical Information Communication Network(TICN). In this paper, we explore a set of data storage methods(external storage, local storage and data storage) and query processing methods in WSN. In particular, we focus on analyzing a novel data structure for supporting the local storage method, named the partial ordered tree(POT). The main idea behind POT is that sensor readings are usually correlated with the physical spatial domain. With the help of POT, only a small portion of sensor nodes participate in query processing tasks, and thus network lifetime is greatly increased. Through a series of simulation experiments, we demonstrate that the POT based local storage method clearly outperforms the existing data storage methods in terms of the energy-efficiency, which directly affects the network lifetime, for processing exact match queries, range queries and top-k queries.

• International Journal of Advanced Culture Technology
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• 제10권2호
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• pp.201-212
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• 2022

With the development of sequencing technology, there is a need for technology to predict the function of the protein sequence. Enzyme Commission (EC) numbers are becoming markers that distinguish the function of the sequence. In particular, many researchers are researching various methods of predicting the EC numbers of protein sequences based on deep learning. However, as studies using various methods exist, a problem arises, in which the exact prediction result of the sequence is unknown. To solve this problem, this paper proposes an All Enzyme Commission (AEC) algorithm. The proposed AEC is an algorithm that executes various prediction methods and integrates the results when predicting sequences. This algorithm uses duplicates to give more weights when duplicate values are obtained from multiple methods. The largest value, among the final prediction result values for each method to which the weight is applied, is the final prediction result. Moreover, for the convenience of researchers, the proposed algorithm is provided through the AllEC web services. They can use the algorithms regardless of the operating systems, installation, or operating environment.

• Investigative Magnetic Resonance Imaging
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• 제16권2호
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• pp.152-158
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• 2012

목적: 뇌내 정맥혈관을 평가하기 위한 조영 증강 자기공명 정맥촬영술의 arterial trigger 와 venous trigger 방법으로 시행한 영상의 차이점을 비교 분석하고자 한다. 대상과 방법: 건강검진을 목적으로 자기공명정맥촬영술을 시행한 41명의 환자들을 대상으로 해면부위의 내경 동맥에서 arterial triggering하여 6초 후에 얻은 영상 (n = 20) 과 상시상 정맥동에서 venous triggering (n = 21) 방법으로 시행한 영상을 후향적으로 분석하였다. 영상은 가돌리늄 조영제 ($Magnevist^{(R)}$, Schering, Germany)를 0.1 mmol/kg 정맥주입하여 시행하였고, 두개강 전반에 대하여 시상영상을 fast spoiled gradiend echo sequence로 시행하였다 (TR/TE 5.2/1.5, matrix $310{\times}310$, 절편수 124 절편, 두께 15 cm). 두 그룹의 영상을 해부학적 정맥 혈관 구조에 따라 17 정맥구역에 대하여 평가하였고, 정맥의 영상품질은 세 단계 (안보임, 일부 보임, 완전히 보임)로 나눠서 평가하였다. 결과: 정맥이 완전히 보인 구역은 arterial triggering 자기공명 정맥 촬영술에서 84% (272/323), venous triggering 자기 공명 정맥촬영술에서 91% (310/340) 이다. Venous triggering 자기공명촬영술과 arterial 자기 공명 정맥촬영술을 비교하였을 때 뇌내 정맥 구조를 평가하는데 있어 venous triggering 방법이 통계적으로 유의하게 높았다 (Fisher exact test, p<0.006). 결론: 조영 증강 자기공명 정맥 촬영술은 정맥 혈관 구조에 대한 고화질의 이미지를 제공하였고 arterial triggering 방법보다 venous triggering 방법이 뇌내 정맥 구조 평가에 우월한 것으로 나타났다.

• 디지털융복합연구
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• 제12권9호
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• pp.353-358
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• 2014

인터렉티브 아트는 관람객들과 상호 작용을 전제로 예술 작품을 구현하는 것으로 가상성, 몰입성, 상호작용성을 특징으로 한다. 그에 따라 관람객이 작품으로 몰입하게 하는 연구는 매우 중요하다. 현재까지 인터렉티브 아트분야에서, 몰입을 측정하기 위해서는 주로 설문지나 인터뷰, 정신 생리학적인 방법을 이용하였다. 그러나 이 방법들은 작품 관람 이후에 진행되어져서 정확한 몰입 측정이 어려우며 작품 관람에 방해를 줄 수 있다. 본 연구에서는 이를 개선하기 위해서 모바일 기기와 카메라를 이용하여 관람객들의 동선을 파악하고 관람시간을 중심으로 한 몰입 측정 방법을 제안한다. 본 논문은 작품의 몰입 정도를 파악하는데 도움을 제공한다.

• Wind and Structures
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• 제6권6호
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• pp.437-450
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• 2003

In this paper, the structural random response due to the turbulent boundary layer excitation is investigated. Using the mode shapes and natural frequencies of an undamped structural operator, a fully analytical model has been assembled. The auto and cross-spectral densities of kinematic quantities are so determined through exact analytical expansions. In order to reduce the computational costs associated with the needed number of modes, it has been tested an innovative methodology based on a scaling procedure. In fact, by using a reduced spatial domain and defining accordingly an augmented artificial damping, it is possible to get the same energy response with reduced computational costs. The item to be checked was the power spectral density of the displacement response for a flexural simply supported beam; the very simple structure was selected just to highlight the main characteristics of the technique. In principle, it can be applied successfully to any quantity derived from the modal operators. The criterion and the rule of scaling the domain are also presented, investigated and discussed. The obtained results are encouraging and they allow thinking successfully to the definition of procedure that could represent a bridge between modal and energy methods.