In gamma-ray spectrometry for volume samples, the self-attenuation effect should be considered in the case of differences in chemical composition and density between the efficiency calibration source for quantitative analysis of sample and the sample actually measured. In particular, the lower the gamma-ray energy, the greater the gamma-ray attenuation due to the self-attenuation effect of the sample. So, the attenuation effect of low-energy gamma-rays in the sample should be corrected to avoid over- or under-estimation of its radioactivity. One of the most important factors in correcting the self-attenuation effect of the sample is the linear attenuation coefficient for the sample, which can be directly calculated using a collimator. The larger the size of the collimator, the more advantageous it is to calculate the linear attenuation coefficient of the sample, but excessive size may limit the use of the collimator in a typical environmental laboratory due to its heavy weight. Therefore, it is necessary to optimize the collimator size and structure according to the measurement environment and purpose. This study is to optimize a collimator that can determine the effective linear attenuation coefficient of low-energy gamma-rays, and verify its applicability. The overall structure of the designed collimator was optimized for gamma-ray energy of less than 100 keV and cylindrical plastic bottle with diameter of 60 mm and a height of 40 mm. The materials of optimized collimator consisted of tungsten. Acryl and acetal were used to form the housing of the collimator, which fixes the central axis of the bottle, collimator and point-like source. In addition, using the housing, the height of the tungsten is adjusted according to the height of the sample. For applicability evaluation of the optimized collimator, IAEA reference material in solid form were used. The sample was filled in the bottle with heights of 1, 2, 3 and 4 cm respectively. Using the collimator and point-like source of 210Pb (46.5 keV), 241Am (59.5 keV), and 57Co (121.1 keV), the linear attenuation coefficient and the radioactivity for the samples were calculated. As a result, to calculate the linear attenuation coefficient using the optimized collimator, a relatively high sample height is required. However, the optimized collimator can be used to determine the linear attenuation coefficients of low-energy gamma-rays for the self-attenuation correction regardless of the sample height. It is concluded that the optimized collimator can be useful to correct the sample selfattenuation effect.

In liquid scintillation counting, sample radioactivity is analyzed by measuring photons emitted from counting vials. Quenching effect lowers photon intensity from samples, which leads to lower counting efficiency. So an appropriate quenching correction according to characteristics of samples is important. In this study, the quenching correction for H-3 analysis was conducted according to the characteristics of paper packaging material leached samples. The leached samples are made from H-3 leaching method which is in the process of development for H-3 contamination screening. There are several ways of quenching correction such as internal standard (IS) method, quench correction curve and triple-to-double coincidence ratio (TDCR) method, etc. For quench correction curve, quenched standard set, which has the same matrix as experimental samples, is needed to be prepared. Each leached sample, however, has different matrix and color depending on condition of leaching experiment, which means that it is not capable of preparing standard set having same matrix with the samples. In this study, the counting samples are used for plotting quench correction curve instead of quenched standard set. Spectral quench parameter of the external standard [SQP(E)] is used as quench indicating parameter (QIP). TDCR and counting efficiencies determined by IS method are used as counting efficiencies. The quench curve of TDCR versus SQP(E) has R2 = 0.55 and the curve of efficiency from IS method versus SQP(E) has R2 = 0.99. TDCR is known for approximate counting efficiency, however, TDCR as counting efficiency needs careful use for H-3 analysis of leached samples. The curve used efficiency from IS method is suitable for H-3 analysis of leached samples. In this study, the quench correction curve is prepared for H-3 analysis of leached samples of paper packaging material. SQP(E), TDCR and efficiency from IS method was used as parameters to plot the quench correction curve, and, the efficiency from IS method is suitable for H-3 analysis of the leached samples. The result of this study can be used for H-3 analysis of leached samples of paper packaging material.

To investigate L2 adolescent learners’ use of machine translation (MT), an MT error correction (EC) test was developed, based on the analysis of MT errors arising from translating the learners’ L1 of middle school EFL textbooks. Learners were also asked to report on their use of MT EC strategies on the EC task. Results indicated that mistranslated sentence and verb tense are the most difficult types of MT errors to correct. Furthermore, to resolve MT errors, guessing from context and literal translations were the two most frequently employed EC strategies. When multiple regression analysis was conducted to examine the contribution of EC strategies to the learners’ ability to correct errors, the mid proficiency learners’ reliance on literal translations and the low proficiency learners’ use of multiple EC strategies were positively associated with improved corrections of MT errors. The results of the study are discussed in light of how L2 learners need to develop competence for using MT in L2 writing.

본 연구에서는 드론을 활용한 변위계측에서 드론의 회전진동 보정을 위해 드론 내부의 가속도계를 이용하는 방법 대신에 드 론 영상 내부의 변위가 발생하지 않는 고정점을 활용한 드론의 회전진동 보정방법을 제안하고자 한다. 영상 내부의 고정점을 활용한 드론 회전진동 보정을 위한 예비 연구로서, 카메라를 고정시킨 후 타겟을 회전하여 회전각도를 측정하는 실험과 회전하는 카메라를 통 해 변위가 발생하는 모형구조물의 변위를 계측하는 실험을 통해 카메라의 회전진동이 발생하는 경우 변위 계측정확도를 검증하였다. 변위가 3mm 이하로 발생 시 카메라 진동이 발생하였을 때 계측 신뢰도가 낮은 반면, 변위가 3mm를 초과하여 발생한 경우 비교적 정 확하게 계측되었다.

교정의 역사와 관점은 중세 이래로부터 다양하게 변화해왔고, 교정의 의미와 패러 다임을 결정하는 중요 요인은 범죄 원인에 관한 철학적 담론 등 이었다. 이에 따라 교정의 양태도 변화되었는데 최근에는 심리학적 접근과 포스트모더니즘의 영향 아래 범죄에 대해 새롭게 이해하려는 노력이 이루어지고 있다. 구체적으로 교정은 교정의 발달사와 철학적 배경, 범죄에 대한 관점, 심리학적 접근 의 이해를 토대로 살펴보면 과거 교정의 패러다임은 몇 가지 제한적 특징을 지닌다. 이에 본 연구에서는 과거 교정의 특성을 살펴보고 인간중심 교정 패러다임을 새롭게 제시하고 실천 전략을 제시해 보고자 한다. 인간중심 교정은 범죄가 아닌 ‘그’ 라는 사람에 관한 관심을 쏟고 범죄자를 교정의 객체로 간주하는 것이 아니라 교정의 주체로 인식하며 능동적 역할을 수행하도록 조 력한다. 즉, 범죄자는 법에 대한 능동적 참여자로 스스로 법체계에 대한 관점을 형성 하고, 법률적 책임에 대한 통찰을 이룰 수 있다는 인식을 전제로 한다. 또한. 인간이 자기 주변에서 일어나는 모든 현상의 중심이 된다는 것으로 그가 자신이 자기 세계에서 일어나는 모든 일의 원인이며 결과이기에 모든 책임을 스스로 지고자 한다는 의미 를 포함하고 있다.

Background: The rounded shoulder posture (RSP) causes the protraction, downward rotation, and anterior tilt of the scapula. Many studies reported that various interventions for the RSP could be helpful for RSP correction. However, no study has reported on the effect of an orthosis on the RSP. Objectives: To investigate the effect of an orthosis on the RSP in comparison with kinesio taping in 32 participants with RSP. Design: Quasi-experimental study. Methods: Thirty-two participants with RSP were randomly assigned into the kinesio taping group (n=15) and orthosis group (n=17). Kinesio taping was applied as follows: 1) both sides of the spine in a vertical direction from C7 to T12. 2) Both sides of the spine in an oblique direction from the coracoid process of the scapula through the acromion to the T12. Orthosis was tried on, and a pull adjustment strap was used to correct the RSP for each participant. Results: Both groups showed significant differences in the height of the acromion to the ground, forward head angle, forward shoulder angle, visual analog scale, and neck disability index within each group. However, no significant differences in all measurements were observed between the two groups. Conclusion: Orthosis for the RSP with exercise would improve the correction of the RSP as much as kinesio taping.

Measurement of the physical properties of high-temperature molten salts is important for the efficient design and operation of molten salt reactors (MSR) in which the reactor coolant and nuclear fuel are in a homogeneous liquid state. Although some crucial physical properties such as viscosity, thermal conductivity, density, etc., have been drawing much attention, relative data, especially for molten chloride salts, are scarce. Thus, it is urgent to prepare the viscosity data as one of the key transport properties in thermal hydraulics analysis. However, it is not an easy task to measure the molten salt viscosity with high accuracy due to end effect, a small gap between the chamber and spindle, thermal expansion of the chamber and spindle at high temperatures in a rotational viscometer. Additionally, molten salt temperatures inside furnace are not uniform due to the large temperature gradient inside the chamber, and therefore the assumption of laminar condition can be violated. In this study, geometric factors, which can be a major interference in the torque measurement, were considered for the accurate determination of the viscosity. We established a high-temperature molten salt viscosity measurement system with Brookfield rotational viscometer. KNO3 molten salt was used as a model substance at a temperature range of 650–773 K. In-house designed spindles and chambers were made of corrosion-resistant alumina. Thermal expansion has a significant influence on the size and shape of the chamber and spindle. The effect of thermal expansion on the conventional correction method was examined with temperature variation and distribution. Gap size variation was also investigated in order to improve the accuracy.

For economic and safe management of Spent Nuclear Fuel (SNF), it is very important to maintain the structural integrity of SNF and to keep the fuel undamaged and handleable. The cladding surrounding nuclear fuel must be protected from physical and mechanical deterioration. The structural evaluation of SNF is very complicated and numerically demanding and it is essential to develop a simplified model for the fuel rod. In this study, a simplified model was developed using a new cladding failure criterion. The simplified model was developed considering only the horizontal or lateral static load utilizing the cladding material properties of irradiated Zirclaoy-4, and applicability in horizontal and vertical drop impacts was investigated. When a fuel rod is subject to bending, a very complicated 3D stress state is generated within the vicinity of the pellet–pellet interface. A very localized stress concentration is observed in the area where the edges of the pellets contact the cladding. If the failure strain criteria obtained from the uniaxial tension test or biaxial tube test is applied, failure is predicted at the beginning stage of loading with premature through-thickness stress or strain development. The localized contact stress or strain is self-limiting and is not a good candidate for the cladding failure criteria. In this work, a new cladding failure criterion is proposed, which can account for the localized stress concentration and the through-thickness stress development. The failure of the cladding is determined by the membrane plus bending stress generated through the thickness of the cladding, which can be calculated by a process called stress linearization along the stress classification line. The failure criterion for SNF was selected as the membrane plus bending stress through stress linearization in the cross-sections through the thickness of the cladding. Because the stress concentration in the cladding around the vicinity of the pellet–pellet interface cannot be simulated in a simplified beam model, a stress correction factor is derived through a comparison of the simplified model and detailed model. The applicability of the developed simplified model is checked through horizontal and vertical drop impact simulations. It is shown that the stress correction factor derived considering static bending loading can be effectively applied to the dynamic impact analyses in both horizontal and vertical orientations.

목적 : 서로 다른 디자인의 시표를 사용하여 원거리 자각적 주시시차 교정 전, 후의 정적 및 동적입체시를 비교 및 분석해 보고자 하였다. 방법 : 12명(남자 7명, 여자 5명)의 시각적 불편함을 느끼는 대상자를 선정하였다. MKH 차트, 차트프로젝터 십자시표를 사용하여 원거리 수평 주시시차를 교정하였고, 주시시차 교정 전, 후의 원거리 정적 및 동적 입체시력, 원거리 입체시깊이를 측정하였다. 결과 : MKH 차트, 차트프로젝터 십자시표에서 자각적으로 측정된 원거리 수평 주시시차 교정 값은 각각 0.77±0.53 △, 0.29±0.30 △으로 측정되었고 유의한 차이가 있었다(p=0.011). 주시시차 교정 전 원거리 정적입 체시력은 102.50±73.99″이었고, MKH 차트, 차트프로젝터 십자시표를 사용한 교정 후는 각각 42.50±29.27″ (p=0.003), 50.00±44.52″(p=0.003)로 유의한 감소가 있었다. 주시시차 교정 전 원거리 동적입체시력은 24.46±6.60″이었고, MKH 차트, 차트프로젝터 십자시표를 사용한 교정 후는 각각 15.26±7.61″(p=0.008), 17.56±5.67″(p=0.019)로 유의한 감소가 있었다. 주시시차 교정 전 원거리 입체시깊이는 1,107.08±52.72 mm 이었고, MKH 차트, 중심융합자극점이 있는 차트프로젝터 십자시표를 사용한 교정 후는 각각 1,136.08±62.40 mm(p=0.002), 1,120.00±51.52 mm(p=0.028)로 유의한 증가가 있었다. 결론 : 시표의 디자인에 따른 원거리 자각적 주시시차 교정 값에는 유의한 차이가 있었고, 주시시차 교정 후의 정적 및 동적입체시는 두 시표에서 모두 유의하게 향상되었다. 따라서 원거리 자각적 주시시차 교정은 입체시의 개선에 긍정적인 효과를 줄 수 있는 것으로 생각된다. 본 연구에서는 MKH 차트를 통해 주시시차를 교정한 후 입 체시가 상대적으로 가장 많이 향상되었다.

위치 기반 AR 게임에서 모바일 기기의 위치를 정확하게 추정하는 것은 중요한 요소 중 하나이다. 모바일 기 기에 내장되어 있는 위치 추정 시스템이 얼마나 정확하게 위치정보를 추정하는 지가 증강되는 AR 콘텐츠의 정확도를 결정한다. 하지만 도시 환경에서는 건물, 건축물, 광고판, 표지판 등 지형지물 및 장애물에 의해서 위치 추정을 위해 필요한 신호가 반사, 굴절, 회절, 차단 등이 발생하게 되고 그로 인하여 모바일 기기의 위 치 추정 시스템으로부터 추정되는 위치에 오차가 생기게 된다. 본 논문에서는 도시 환경에서 모바일 기기의 위치 오차가 증가하는 현상에 대해서 상용 스트리트 뷰와 문자 태그를 활용하여 심플하면서도 신뢰성 있는 위치 보정 방안을 제안한다. 제안하는 위치 보정 방안은 쿼리 이미지와 스트리트 뷰 파노라마 이미지로부터 생성된 문자 태그를 대조하는 것을 통해서 매칭 스코어를 계산한고 매칭 스코어에 따라 쿼리 이미지를 촬영 한 실제 위치와 가까운 스트리트 뷰를 검색하는 것을 통해서 모바일 기기의 위치를 보정한다. 제안하는 위치 보정 방안은 위치 오차가 43.71m인 위치를 위치 오차가 4.09m인 위치로 보정하였으며 낮과 밤에 관계없이 위치를 보정할 수 있다는 장점이 있다.

It is dicult for observers to conduct an optical alignment at an observatory without the assistance of an optical engineer if optomechanical parts are to be replaced at night. We present a prac- tical tilt correction method to obtain the optimal optical alignment condition using the symmetricity of optical aberrations of a wide-eld on-axis telescope at night. We conducted coarse tilt correction by visually examining the symmetry of two representative star shapes obtained at two guide chips facing each other, such as east{west or north{south pairs. After coarse correction, we observed four sets of small stamp images using four guide cameras located at each cardinal position by changing the focus positions in 10-m increments and passing through the optimum focus position in the range of 200 m. The standard deviation of each image, as a function of the focus position, was tted with a second-order polynomial function to derive the optimal focus position at each cardinal edge. We derived the tilt angles from the slopes converted by the distance and the focus position dierence between two paired guide chip combinations such as east{west and north{south. We used this method to collimate the on-axis wide-eld telescope KMTNet in Chile after replacing two old focus actuators. The total optical alignment time was less than 30 min. Our method is practical and straightforward for maintaining the optical performance of wide-eld telescopes such as KMTNet.

본 연구는 현재 마약중독에서 회복되었고 마약 밀매를 하지 않는 남성으로 과거의 마약 밀매 경험을 탐색하여 밀매의 구조적 변화와 밀매 전략, 밀매조직을 살펴보고 이를 근거로 마약 밀매자의 중독회복과 마약 공급차단 정책 수립을 위한 교정차원의 정책마련의 기초자료를 제공하는데 목적이 있다. 연구 참여자 선정은 마약밀매 경험이 7년 이상, 마약중독에서 최소 3년 이상 회복을 유지하고 있는 5인을 대상으로 하였다. 자료수집은 1대1 심층 면담을 통해 자료를 수집하였으며, 수집 된 자료는 Creswell(2013)의 사례연구방법으로 분석하였다. 연구는 마약 밀매자의 마약밀매 과정을 시간 흐름에 따른 현상의 동태적 과정과 결과를 분석하고, 특히 맥락을 이해하고 자 하였다. 그 결과 4개의 분석영역, 11개의 범주와 39개 개념결집이 도출되었다. 첫째, 진입동기에서는 마이다스의 비즈니스와 사회적 지위의 초고속상승, 가난한 자의 꿈으로 나타났다. 둘째, 마약공급 조직에서는 항구적 상선구축, 불신과 배신구조, 믿음의 근원 현금으로 나타났다. 셋째, 소비시장 확장전략에서는 주변지인 공략, 다단계식 밀매조직, 중독의 무한루프에 가두기로 나타났다. 넷째, 사회관계에서는 평범의 가면 쓰기, 거짓 봉사로 나타났다. 이러한 연구결과를 토대로 마약밀매자로 부터 마약 예비중독자와 중독재발의 위험이 있는 개인을 보호할 수 있는 공급차단정책과 수요감 소정책을 통해 마약밀매자의 회복을 위한 교정정책차원의 논의 및 제언하였다.