We complete the survey for finite-source/point-lens (FSPL) giant-source events in 2016–2019 KMTNet microlensing data. The 30 FSPL events show a clear gap in Einstein radius, 9 μas < θE < 26 μas, which is consistent with the gap in Einstein timescales near tE ∼ 0.5 days found by Mr´oz et al. (2017) in an independent sample of point-source/point-lens (PSPL) events. We demonstrate that the two surveys are consistent. We estimate that the 4 events below this gap are due to a power-law distribution of freefloating planet candidates (FFPs) dNFFP/d logM = (0.4 ± 0.2) (M/38 M⊕)−p/star, with 0.9 ≲ p ≲ 1.2. There are substantially more FFPs than known bound planets, implying that the bound planet power-law index γ = 0.6 is likely shaped by the ejection process at least as much as by formation. The mass density per decade of FFPs in the Solar neighborhood is of the same order as that of ‘Oumuamua-like objects. In particular, if we assume that ‘Oumuamua is part of the same process that ejected the FFPs to very wide or unbound orbits, the power-law index is p = 0.89 ± 0.06. If the Solar System’s endowment of Neptune-mass objects in Neptune-like orbits is typical, which is consistent with the results of Poleski et al. (2021), then these could account for a substantial fraction of the FFPs in the Neptune-mass range.

We present the analysis of a planetary microlensing event OGLE-2019-BLG-0362 with a shortduration anomaly (∼0.4 days) near the peak of the light curve, which is caused by the resonant caustic. The event has a severe degeneracy with Δχ2 = 0.9 between the close and the wide binary lens models both with planet-host mass ratio q ≃ 0.007. We measure the angular Einstein radius but not the microlens parallax, and thus we perform a Bayesian analysis to estimate the physical parameters of the lens. We find that the OGLE-2019-BLG-0362L system is a super-Jovian-mass planet Mp = 3.26+0.83 −0.58 MJ orbiting an M dwarf Mh = 0.42+0.34 −0.23 M⊙ at a distance DL = 5.83+1.04 −1.55 kpc. The projected star-planet separation is a⊥ = 2.18+0.58 −0.72 AU, which indicates that the planet lies beyond the snow line of the host star.

인간의 평균수명 연장으로 일상생활을 수행하기 어려운 노인들은 개인의 욕구에 맞는 요양서비스를 필요로 하고 있으며, 노인의 신체활동이나 가사활동 등의 개별화된 서비스 를 제공하는 요양보호사의 일자리는 지속해서 증가하고 있다. 본 연구의 목적은 노인의 료복지시설의 요양보호사가 인지하고 있는 현재의 사회적 지지가 서비스 질에 미치는 영향을 분석하고, 직무만족과 직무스트레스의 매개효과를 검증하여 요양서비스 질을 향 상하는 것에 있다. 본 연구는 서울, 경기, 인천지역의 의료복지시설에 근무하고 있는 요양보호사 488명을 대상으로 하였으며, SPSS WIN 24.0과 AMOS 24.0 프로그램을 사용하여 분석하였다. 본 연구의 결과는 구조모형을 통해 연구 변인 간 영향 관계를 검증한 결과, 요양보호 사의 사회적 지지는 직무만족에 유의한 정(+)적 영향을 미쳤고, 직무스트레스에는 유의 한 부(-)적 영향을 미쳤다. 직무만족은 서비스 질에 유의한 정(+)적 영향을 미쳤고, 직무 스트레스는 서비스 질에 유의한 부(-)적 영향을 미쳤다. 또한 요양보호사의 사회적 지지 와 서비스 질 관계에서 직무만족은 매개역할을 하는 것으로 검증되었다. 따라서 요양보 호사의 사회적 지지는 직무만족을 매개하여 서비스 질에 간접적으로 영향을 미치는 것 으로 검증되었다. 본 논문은 요양보호사의 사회적 지지가 서비스 질에 미치는 영향에서 직무만족과 직 무스트레스의 매개효과를 검증함으로써 변수 간의 구조적 관계를 설명하고 요양보호사 의 사회적 지지가 요양서비스 질의 수준을 높여 요양보호 대상자들의 삶의 질을 향상하 는 실천적 방안을 마련하였다.

본 연구목적은 노인의 노후준비도가 생활만족도에 미치는 영향을 분석하고 그 영향 관계에서 자기효능감의 매개효과를 검증하고자 한다. 연구대상은 수 도권 지역에서 은퇴를 준비한 중년 이후 노인 425명을 대상으로 하였다. 분석방 법은 기술통계 및 상관분석, 매개모형을 분석하였다. 연구결과는 다음과 같다. 첫째, 노인의 노후준비도는 생활만족도에 정적인 영향을 미치는 것으로 나타났 다. 둘째, 노인의 노후준비도는 자기효능감에 정적인 영향을 미치는 것으로 나타 났다. 셋째, 자기효능감은 생활만족도에 정적인 영향을 미치는 것으로 나타났다. 넷째, 노후준비도와 생활만족도의 관계에서 자기효능감은 매개역할을 하는 것으 로 나타났다. 이런 연구결과를 토대로 노인의 생활만족도 향상을 위한 실천 방안 을 제시하였다.

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.

We report the discovery of a giant exoplanet in the microlensing event OGLE-2017-BLG-1049, with a planet―host star mass ratio of q = 9.53 ± 0.39 × 10-3 and a caustic crossing feature in Korea Microlensing Telescope Network (KMTNet) observations. The caustic crossing feature yields an angular Einstein radius of θE = 0.52 ± 0.11 mas. However, the microlens parallax is not measured because the time scale of the event, tE ≃ 29 days, is too short. Thus, we perform a Bayesian analysis to estimate physical quantities of the lens system. We find that the lens system has a star with mass Mh = 0.55+0.36 -0.29 M⊙ hosting a giant planet with Mp = 5.53+3.62 -2.87 MJup, at a distance of DL = 5.67+1.11 -1.52 kpc. The projected star{planet separation is aㅗ = 3.92+1.10 -1.32 au. This means that the planet is located beyond the snow line of the host. The relative lens{source proper motion is μrel ~ 7 mas yr-1, thus the lens and source will be separated from each other within 10 years. After this, it will be possible to measure the flux of the host star with 30 meter class telescopes and to determine its mass.

At q = 1.81 ± 0.20 × 10-5, KMT-2018-BLG-0029Lb has the lowest planet-host mass ratio q of any microlensing planet to date by more than a factor of two. Hence, it is the first planet that probes below the apparent "pile-up" at q = 5-10 ×10-5. The event was observed by Spitzer, yielding a microlens-parallax πE measurement. Combined with a measurement of the Einstein radius θE from finite-source effects during the caustic crossings, these measurements imply masses of the host Mhost = 1.14+0.10-0.12 M⊙ and planet Mplanet = 7.59+0.75-0.69 M⊕, system distance DL = 3.38+0.22-0.26 kpc and projected separation a⊥ = 4.27+0.21-0.23 AU. The blended light, which is substantially brighter than the microlensed source, is plausibly due to the lens and could be observed at high resolution immediately.

토지이용별로 토양 물리성 변화를 평가하기 위하여 2009년부터 2017년까지 전국의 밭, 과수원, 논을 대상으로 토양물리성 특성을 4년 주기로 분석하였다. 밭은 작토심, 심토 유기물 함량, 심토 산중식 경도가 증가하고 심토 용적밀도가 감소하며, 개량기준 초과비율도 지속적으로 감소하였다. 과수원은 경운심이 증가하였으나 심토 유기물 함량이 감소하고 적정기준을 초과하는 비율은 4년 전보다 증가하였다. 논은 작토심, 심토 유기물 함량이 감소하고 심토 용적밀도가 증가하며 개량기준 초과비율이 증가하는 등 물리성 불량이 심화되었다. 최근 10년간 밭, 과수원에 비해 논의 물리성이 악화되는 것을 확인할 수 있었으며, 공통적으로 심토 유기물 함량이 감소하고 심토 용적밀도가 증가하는 주요한 요인은 토양유기물로 평가되었다. 따라서 토양물리성 질 관리에 유기물은 중요한 요소이었으며, 특히 논에서 지속적인 유기물 관리와 경운방법 개선 등이 필요하다.

Despite the accident rate for fishing vessels accounts for 70% of all maritime accidents, few studies on such accidents have been done and most of the them mainly focus on causes and mitigation policies to reduce that accident rate. Thus, this risk analysis on sea accidents is the first to be performed for the successful and efficient implementation of accident reducing measures. In risk analysis, risk is calculated based on the combination of frequency and the consequence of an accident, and is usually expressed as a single number. However, there exists uncertainty in the risk calculation process if one uses a limited number of data for analysis. Therefore, in the study we propose a probabilistic simulation method to forecast risk not as a single number, but in a range of possible risk values. For the capability of the proposed method, using the criteria with the ALARP region, we show the possible risk values spanning across the different risk regions, whereas the single risk value calculated from the existing method lies in one of the risk regions. Therefore, a decision maker could employ appropriate risk mitigation options to handle the risks lying in different regions. For this study, we used fishing vessel accident data from 1988 to 2016.

Phosphorus (P) is a limited, essential, and irreplaceable nutrient for the biological activity of all the living organisms. Sewage sludge ash (SSA) is one of the most important secondary P resources due to its high P content. The SSA has been intensively investigated to recover P by wet chemicals (acid or alkali). Even though H2SO4 was mainly used to extract P because of its low cost and accessibility, the formation of CaSO4 (gypsum) hinders its use. Heavy metals in the SSA also cause a significant problem in P recovery since fertilizer needs to meet government standards for human health. Therefore, P recovery process with selective heavy metal removal needs to be developed. In this paper some of the most advanced P recovery processes have been introduced and discussed their technical characteristics. The results showed that further research is needed to identify the chemical mechanisms of P transformation in the recovery process and to increase P recovery efficiency and the yields.