• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제14권1호
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• pp.31-39
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• 2008

센서노드 운영체제는 다종다양한 센서를 효율적으로 관리하기 위해서 통일된 API와 효율적인 디바이스 드라이버 매니저를 지원하여야 한다. 하지만 Tiny-OS, Nano-Q+ 등의 기존 운영체제들은 이와 같은 디바이스 드라이버 매니저를 지원하지 않는다. 본 논문에서는 센서 I/O 서브시스템을 제안하여 응용프로그래머에게 통일된 API를 제공하며 디바이스 드라이버의 장탈착이 용이한 디바이스 관리 매니저를 제시한다. 탈부착이 가능한 스마트 센서를 위하여 원격 디바이스 드라이버 업데이트 방식을 제안한다. 이 방식은 일부 센서가 변경되었을 때 전체 응용이 아닌 디바이스 드라이버만의 다운로딩이 가능하다. ETRI가 개발한 Nano-Q+에 상기한 기능을 추가하여 설계하고 구현하였다. 기존 운영체제와 성능을 비교 평가하였고 디바이스 드라이버 부분 다운로딩이 다운로딩 속도를 획기적으로 개선시켰다.

• Journal of Nutrition and Health
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• 제46권3호
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• pp.218-225
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• 2013

Although the functional ingredient has been evaluated by the Korea Food and Drug Administration (KFDA) based on scientific evidence, the levels of scientific evidence and consistency of the results might vary according to emerging data. Therefore, periodic re-evaluation may be needed for some functional ingredients. In this study, we re-evaluated scientific evidence for the antioxidant activity of coenzyme Q10 as a functional ingredient in health functional food. Literature searches were conducted using the Medline and Cochrane, KISS, and IBIDS databases for the years 1955-2010 with the search term of coenzyme Q10 in combination with antioxidant. The search was limited to human studies published in Korean, English, and Japanese. Using the KFDA's evidence based evaluation system for scientific evaluation of health claims, 33 human studies were identified and reviewed in order to evaluate the strength of the evidence supporting a relation between coenzyme Q10 and antioxidant activity. Among 33 studies, significant effects for antioxidant activities were reported in 22 studies and their daily intake amount was 60 to 300 mg. Based on this systematic review, we concluded that there was possible evidence to support a relation between coenzyme Q10 intake and antioxidant activities. However, because inconsistent results have recently been reported, future studies should be monitored.

• 한국산학기술학회논문지
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• 제17권1호
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• pp.572-584
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• 2016

본 연구는 인간의 주관성을 탐구할 수 있는 Q 방법론을 이용하여 여자간호사가 인식하는 남자간호사의 유형과 특성을 확인하고자 수행하였다. 35명의 P 표본에게 35개의 Q 표본을 9점 척도 상에 정규 분포의 형태로 분류하게 하였다. 수집된 자료는 PC-QUANL 프로그램으로 처리하였다. 연구결과, 남자간호사에 대한 인식은 3개의 유형으로 확인되었으며, 제1유형은 '발전 지향적 옹호형', 제2유형은 '현실적 비판형', 제3유형은 '보수주의적 수용형'으로 분류되었다. 각 유형 간 공통된 견해는 '남자간호사는 여성 집단의 고유한 특성으로 인해 스트레스를 받는다'로 나타났다. 본 연구결과는 세 가지 유형에 근거한 중재 프로그램을 개발하여 남자간호사에 대한 여자간호사의 인식을 향상시키는 데 기여할 것이다.

• Geomechanics and Engineering
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• 제34권5호
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• pp.491-505
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• 2023

The practical usage of underground space and demand for vehicular tunnels necessitate the construction of non-circular wide rectangular tunnels. However, constructing large tunnels in soft clayey soil conditions with no ground improvement can lead to excessive ground deformations and collapse. In recent years, in situ ground improvement techniques such as jet grouting and deep cement mixing are often utilized to perform cement-stabilisation around the tunnel boundary to prevent large deformations and failure. This paper discusses the stability characteristics and failure behaviour of a wide rectangular tunnel in cement-treated soft clays. First, the plane strain finite element model is developed and validated with the results of centrifuge model tests available in the past literature. The critical tunnel support pressures computed from the numerical study are found to be in good agreement with those of centrifuge model tests. The influence of varying strength and thickness of improved soil surround, and cover depth are studied on the stability and failure modes of a rectangular tunnel. It is observed that the failure behaviour of the tunnel in improved soil surround depends on the ratio of the strength of improved soil surround to the strength of surrounding soil, i.e., q_ui/q_us, rather than just q_ui. For low q_ui/q_us ratios,the stability increases with the cover; however, for the high strength improved soil surrounds with q_ui >> q_us, the stability decreases with the cover. The failure chart, modified stability equation, and stability chart are also proposed as preliminary design guidelines for constructing rectangular tunnels in the improved soil surrounded by soft clays.

• Geomechanics and Engineering
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• 제21권6호
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• pp.503-511
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• 2020

This study evaluated the side resistance of drilled shafts socketed into rock sections. Commonly used analysis methods for side resistance of piles in rocks are examined by utilizing a large number of load test data. The analysis of the unit side resistance of pile foundations embedded into rock sections is based on an empirical coefficient (α) and the uniaxial compressive strength (q_u) or its root (${\sqrt{q_u}}$). The Davisson criterion was used to interpret the resistance capacity from the load test results to acquire the computed relationships. The α-${\sqrt{q_u}}$ relationship is proven to be reliable in the prediction of friction resistance. This study further analyzed the relationship by including the effect of rock quality designation (RQD) on the results. Analysis results showed that the analysis model of α-${\sqrt{q_u}}$-RQD provided better prediction and reliability considering the RQD classification. Based on these analyses, the side resistance of drilled shafts socked into rocks is provided with statistical data to support the analysis.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 암반역학위원회 학술세미나 논문집
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• pp.119-137
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• 2003

Electrical resistivity is one of physical property of the earth and measured by electrical resistivity survey, electrical resistivity logging and laboratory test. Recently, electrical resistivity Is widely used In determination of rock quality in road and railway tunnel design. To get more reliable rock quality data from electrical resistivity, it needs a lot of test and study on correlation of resistivity and rock quality. Firstly, we did rock property test In laboratory, such as uniaxial compressive strength(UCS), P wave velocity, Young's modulus and electrical resistivity. We correlate each test results and we found out that electrical resistivity has exponentially related to UCS and P wave velocity and linearly related to Young's modulus. And we accomplished electrical resistivity survey in field site and carried out electrical resistivity togging at In-situ area. Also we performed rock classification, such as RQD, RMR and Q-system and we correlate electrical resistivity to rock classification results. We found out that electrical resistivity logging data are highly correlate to RQD, Q and RMR. Also we found out that electrical resistivity survey data are lower than electrical resistivity logging data when there are faults or fractures. And it cause electrical resistivity survey data to lowly correlate to RQD, Q and RMR.

• Journal of Power Electronics
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• 제12권5호
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• pp.821-829
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• 2012

This research article presents a novel approach based on an instantaneous active and reactive power component (p-q) theory for generating reference currents for shunt active filter (SHAF). Three-phase reference current waveforms generated by proposed scheme are tracked by the three-phase voltage source converter in a hysteresis band control scheme. The performance of the SHAF using the p-q control strategy has been evaluated under various source conditions. The performance of the proposed control strategy has been evaluated in terms of harmonic mitigation and DC link voltage regulation. In order to maintain DC link voltage constant and to generate the compensating reference currents, we have developed Fuzzy logic controller with different (Trapezoidal, Triangular and Gaussian) fuzzy M.F.s. The proposed SHAF with different fuzzy M.F.s is able to eliminate the uncertainty in the system and SHAF gains outstanding compensation abilities. The detailed simulation results using MATLAB/SIMULINK software are presented to support the feasibility of proposed control strategy. To validate the proposed approach, the system is also implemented on a real time digital simulator and adequate results are reported for its verifications.

• 한국산학기술학회논문지
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• 제13권4호
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• pp.1759-1768
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• 2012

본 연구는 한 대학병원에 근무하고 있는 간호사들의 피로수준을 파악하고, 인구사회학적 특성, 건강관련행위 특성, 직업관련 특성 및 직무스트레스 내용과 피로수준과의 관련성을 규명하고자 하였다. 조사대상은 대전광역시의 한 대학병원에 근무하고 있는 전체 간호사 726명을 대상으로 계통추출법에 의해 추출한 450명으로 하였으며, 조사는 2010년 10월 1일부터 10월 31일까지의 기간 동안에 구조화된 무기명 자기기입식 설문지를 이용한 설문조사에 의하였다. 연구 결과, 조사대상자의 피로수준의 분포는 정상 군이 75.1%, 고위험 피로 군이 24.9%이었으며, 직무스트레스 내용별 고위험피로수준의 분포는 업무요구도가 높을수록, 업무의 자율성이 낮을수록, 상사의 지지도가 낮을수록 유의하게 높았다. 또한 피로수준은 업무요구도와 유의한 양의 상관관계를 보인 반면, 업무의 자율성, 상사의 지지도와는 유의한 음의 상관관계를 보였다. 로지스틱 회귀분석 결과, 다른 변수를 통제한 다변량 모델에서 업무요구도는 가장 낮은 군(Q1)에 비해 높은 군(Q3, Q4)에서, 고위험 피로 군에 속할 위험도가 유의하게 증가한 반면, 업무의 자율성은 가장 낮은 군(Q1)에 비해 높은 군(Q3, Q4)에서 고위험 피로 군에 속할 위험도가 유의하게 감소하였다. 결론적으로 조사대상 간호사들이 경험하는 직무스트레스 내용은 독립적으로 피로수준에 영향을 미치는 요인임이 확인되었다.

• Geomechanics and Engineering
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• 제35권5호
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• pp.539-554
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• 2023

This article is dedicated to the pursuit of establishing a robust empirical relationship that allows for the estimation of in-situ modulus of deformations (E_m and G_m) within sedimentary rock slope masses through the utilization of Q_slope values. To achieve this significant objective, an expansive and thorough methodology is employed, encompassing a comprehensive field survey, meticulous sample collection, and rigorous laboratory testing. The study sources a total of 26 specimens from five distinct locations within the South Pars (known as Assalouyeh) region, ensuring a representative dataset for robust correlations. The results of this extensive analysis reveal compelling empirical connections between E_m, geomechanical characteristics of the rock mass, and the calculated Q_slope values. Specifically, these relationships are expressed as follows: E_m = 2.859 Q_slope + 4.628 (R² = 0.554), and G_m = 1.856 Q_slope + 3.008 (R² = 0.524). Moreover, the study unravels intriguing insights into the interplay between in-situ deformation moduli and the widely utilized Rock Mass Rating (RMR) computations, leading to the formulation of equations that facilitate predictions: RMR = 18.12 E_m0.460 (R² = 0.798) and RMR = 22.09 G_m0.460 (R² = 0.766). Beyond these correlations, the study delves into the intricate relationship between RMR and Rock Quality Designation (RQD) with Qslope values. The findings elucidate the following relationships: RMR = 34.05e^0.33Qslope (R² = 0.712) and RQD = 31.42e^0.549Qslope (R² = 0.902). Furthermore, leveraging the insights garnered from this comprehensive analysis, the study offers an empirically derived support system tailored to the distinct characteristics of discontinuous rock slopes, grounded firmly within the framework of the Q_slope methodology. This holistic approach contributes significantly to advancing the understanding of sedimentary rock slope stability and provides valuable tools for informed engineering decisions.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 추계학술대회 논문집
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• pp.165-166
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• 2008