This study investigated changes in psychological stress levels of 60 firefighters after participation in an eight-week Equine-Assisted Learning (EAL) program consisting of 16 sessions. The Korean versions of the Posttraumatic Diagnosis Scale (PDS-K), the Center for Epidemiological Studies Depression Scale (K-CESD), and the Difficulties in Emotional Regulation Scale (K-DERS) were used for measurements. Participants were divided into two groups according to level of posttraumatic stress symptoms (PTSS): the PTSS risk group and the PTSS non-risk group. Results showed that PDS-K, K-CESD, and K-DERS scores were significantly reduced after the program in the PTSS risk group. Significant reduction was also found in all sub-scales of PDS-K: re-experiencing, avoidance/emotional numbing, and hyperarousal. Moreover, in the PTSS risk group, there were greater improvements with significant group x time interactions. These findings suggest that EAL is effective in relieving PTSD and PTSD-related symptoms of firefighters with subsyndromal or more severe levels of PTSD.

North Korea continues to upgrade and display its long-range rocket launchers to emphasize its military strength. Recently Republic of Korea kicked off the development of anti-artillery interception system similar to Israel’s “Iron Dome”, designed to protect against North Korea’s arsenal of long-range rockets. The system may not work smoothly without the function assigning interceptors to incoming various-caliber artillery rockets. We view the assignment task as a dynamic weapon target assignment (DWTA) problem. DWTA is a multistage decision process in which decision in a stage affects decision processes and its results in the subsequent stages. We represent the DWTA problem as a Markov decision process (MDP). Distance from Seoul to North Korea’s multiple rocket launchers positioned near the border, limits the processing time of the model solver within only a few second. It is impossible to compute the exact optimal solution within the allowed time interval due to the curse of dimensionality inherently in MDP model of practical DWTA problem. We apply two reinforcement-based algorithms to get the approximate solution of the MDP model within the time limit. To check the quality of the approximate solution, we adopt Shoot-Shoot-Look(SSL) policy as a baseline. Simulation results showed that both algorithms provide better solution than the solution from the baseline strategy.

Organic scintillator is easy to manufacture a large size and the fluorescence decay time is short. However, it is not suitable for gamma measurement because it is composed of a low atomic number material. Organic scintillation detectors are widely used to check the presence or absence of radiation. The fluorescence of organic scintillators is produced by transitions between the energy levels of single molecules. In this study, an organic scintillator development study was conducted for use in gamma measurement, alternative materials for secondary solute used in basic organic scintillators were investigated, and the availability of alternative materials, detection characteristics, and neutron/gamma identification tests were performed. In other words, a secondary solute showing an improved energy transfer rate than the existing material was reported, and the performance was evaluated. 7-Diethylamino -4-methylcoumarin (DMC), selected as an alternative material, is a benzopyrone derivative in the form of colorless crystals, has high fluorescence and high quantum yield in the visible region, and has excellent light stability. In addition, it has a large Stokes shift characteristic, and solubility in solvent is good. Through this study, it was analyzed that the absorption wavelength range of DMC coincided with the emission wavelength range of PPO, which is the primary solute. Through this study, it was confirmed that the optimal concentration of DMC was 0.04wt%. As a result of performing gamma and neutron measurement tests using a DMC-based liquid scintillator, it showed good performance (FOM=1.42) compared to a commercial liquid scintillator. Therefore, the possibility of use as a secondary solute was demonstrated. Based on this, if studies on changes in the composition of secondary solute or the use of nanoparticles are conducted, it will be possible to manufacture and utilize a scintillator with improved efficiency compared to the existing scintillator.

The safe, efficient and cost-effective decommissioning and dismantling of radioactive facilities requires the accurate characterization of the radionuclide activities and dose rate environment. And it is critical across many nuclear industries to identify and locate sources of radiation accurately and quickly. One of the more challenging aspects of dealing with radiation is that you cannot see it directly, which can result in potential exposure when working in those environments. Generally, semiconductor detectors have better energy resolution than scintillation detectors, but the maximum achievable count rates are limited by long pulse signals. Whereas some high pure germanium detectors have been developed to operate at high count rates, and these HPGe detectors could obtain gamma-ray spectra at high count rates exceeding 1 Mcps. However, HPGe detectors require cooling devices to reduce the leak currents, which becomes disadvantageous when developing portable radiation detectors. Furthermore, chemicalcompound semiconductor detectors made of cadmium telluride and cadmium zinc telluride are popular, because they have good energy resolution and are available at room temperature. However, CdTe and CZT detectors develop irradiation-induced defects under intense gamma-ray fields. In this Review, we start with the fundamentals of gamma rays detection and review the recent developments in scintillators gamma-ray detectors. The key factors affecting the detector performance are summarized. We also give an outlook on the field, with emphasis on the challenges to be overcome.

기후 변화의 가속화로 국내 제주 및 남부 지방을 중심으로 열대 및 아열대 작물의 재배 및 소비가 증가하는 추세이다.오크라는 식용적 가치가 있을 뿐만 아니라, 품종별 고유의 꼬 투리와 잎의 색은 관상적 가치가 있어 조경 식물로 많이 사용 되고 있다. 본 연구는 도심 내 옥상 온실에 관상식물인 오크 라를 도입하기 위해 피트모스와 펄라이트 비율에 따른 기초 종자 발아 및 육묘기 실험을 진행하였다. 피트모스와 펄라이 트 비율은 PT:PL=1:2, 1:1, 2:1, 4:1 네 가지로 조성하였다. 발 아율은 파종 후 7일차부터 다른 처리구에 비해 피트모스:펄라 이트=1:2의 처리구에서 가장 높았다. 파종 후 28일차와 70일 차에 줄기길이, 경경, 뿌리길이, 지상부와 지하부의 생체중과 건물중 그리고 엽면적은 피트모스:펄라이트=1:2 처리구에서 가장 높았다. 그러나, 파종 후 56일 이후부터 엽수는 피트모 스:펄라이트=1:2, 2:1, 4:1 처리구에서 감소하였다. 피트모스: 펄라이트=1:1, 2:1, 4:1 처리구에서 식물이 필요로 하는 피트 모스의 비율이 지나치게 높아 높은 피트모스 비율로 인하여 수분함수량이 과도하게 높아 식물이 고사한 것으로 판단된다. 따라서 오크라를 관상식물로 활용하기 위해서는 피트모스와 펄라이트를 1:2로 혼합한 배지가 가장 적합하다.

Polarimetric measurements of the lunar surface from lunar orbit soon will be available via Wide-Field Polarimetric Camera (PolCam) onboard the Korea Pathfinder Lunar Orbiter (KPLO), which is planned to be launched in mid 2022. To provide calibration data for the PolCam, we are conducting speckle polarimetric measurements of the nearside of the Moon from the Earth’s ground. It appears that speckle imaging of the Moon for scientific purposes has not been attempted before, and there is need for a procedure to create a “lucky image” from a number of observed speckle images. As a first step of obtaining calibration data for the PolCam from the ground, we search for the best sharpness measure for lunar surfaces. We then calculate the minimum number of speckle images and the number of images to be shift-and-added for higher resolution (sharpness) and signal-to-noise ratio.