• International Journal of Computer Science & Network Security
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• 제21권2호
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• pp.21-39
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• 2021

The acceptance of smartphone applications in the learning field is one of the most significant challenges for higher education institutions in Saudi Arabia. These institutions serve large and varied sectors of society and have a tremendous impact on the knowledge gained by student segments at various ages. M-learning is of great importance because it provides access to learning through a wide range of mobile networks and allows students to learn at any time and in any place. There is a lack of quality requirements for M-learning applications in Saudi societies partly because of mandates for high levels of privacy and gender segregation in education (Garg, 2013; Sarrab et al., 2014). According to the Saudi Arabian education ministry policy, gender segregation in education reflects the country's religious and traditional values (Ministry of Education, 2013, No. 155). The opportunity of many applications would help the Saudi target audience more easily accept M-learning applications and expand their knowledge while maintaining government policy related to religious values and gender segregation in the educational environment. In addition, students can share information through the online framework without breaking religious restrictions. This study uses a quantitative perspective to focus on defining the technical aspects and learning requirements for distributing knowledge among students within the digital environment. Additionally, the framework of the unified theory of acceptance and use of technology (UTAUT) is used to modify new constructs, called application quality requirements, that consist of quality requirements for systems, information, and interfaces.

• Journal of the Korean Wood Science and Technology
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• 제32권6호
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• pp.67-73
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• 2004

The influence of liquefied wood (LW) on the mechanical and thermal properties of liquefied wood-polymer composites (LWPC) was investigated in this study. The thermal behaviors of LWPC were characterized by means of thermogravimetric (TGA) and differential scanning calorimetric (DSC) analyses. LW showed significant effects on the mechanical strength properties. The increase of flexural MOE and Young's modulus was related to the increase of stiffness of LWPC. The effect of LW was also significant on the flexural and tensile MOR. The impact strength decreased with the increase of LW application level. With the increased stress concentration by the poor bonding between LW and polymer, the impact strength of LWPC decreased, compared with that of high-density polyethylene (HDPE). The thermal stability of LWPC decreased with the increase of LW content up to 40%. The melting temperature of HDPE decreased with the increase of LW loading level. Enthalpy of HDPE also decreased with the addition of LW. This study proves the thermal stability necessary for the consolidation of composition materials.

• Imaging Science in Dentistry
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• 제52권4호
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• pp.435-440
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• 2022

Mucormycosis is a rare, invasive fungal infection that progresses aggressively and requires prompt surgery and appropriate treatment. The number of cases of mucormycosis in coronavirus disease 2019 (COVID-19) patients has recently increased, and patients with uncontrolled diabetes mellitus are particularly at an elevated risk of infection. This report presents a case of mucormycosis-related osteomyelitis of the maxilla in a 37-year-old man with diabetes mellitus. The patient complained of severe and persistent pain in the right maxilla, accompanied by increased tooth mobility and headache. On contrast-enhanced computed tomographic images, gas-forming osteomyelitis of the right maxilla was observed. Destruction of the maxilla and palatine bone then proceeded aggressively. Sequestrectomy was performed on the right maxilla, and the histopathological diagnosis was mucormycosis. Further investigation after the first operation revealed the patient's history of COVID-19 infection.

• 한국시뮬레이션학회논문지
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• 제19권2호
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• pp.51-62
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• 2010

모델링 및 시뮬레이션 기술은 실 전장 환경과 유사한 실험환경을 컴퓨터상에 구성하여 무기 체계에 대한 효과도를 효율적으로 실제와 유사하게 분석 할 수 있도록 한다. 그러나 기 개발된 무기체계 모델들은 각 시뮬레이션 목적에 맞도록 편중 개발되어 재사용성이 낮으며, 개발된 무기체계 모델을 수행하기 위한 모의엔진의 구조도 서로 상이하여 확장성 측면에서 한계를 갖고 있다. 본 논문에서는 무기체계 분석을 위해 국방 M&S 모의 엔진에서 제공해야 할 요구사항을 식별하고, 식별된 요구사항을 반영하는 모의 엔진의 소프트웨어 아키텍처를 정의한다. 정의된 아키텍처는 모델러에게 사용상 편이성을 제공하고, 컴포넌트 기반의 재사용, 다양한 사용자 범주, 최대화된 연동능력, 모델링 및 시뮬레이션 전체 단계에 걸친 재사용을 지원하도록 설계 되었다.

• Current Optics and Photonics
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• 제7권2호
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• pp.136-146
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• 2023

Based on calculations using the macroscopic Maxwell's equations with mesoscopic boundary conditions, light absorption by a layered metal-insulator-metal (MIM) metamaterial system embedded in three different environments is investigated. Increasing the top metal thickness shifts the broad absorption band to lower dielectric-constant regions and longer wavelengths, for either TM or TE waves. Boosting the dielectric-layer thickness redshifts the broadband absorption to regions of larger dielectric constant. In air, for the dielectric-constant range of 0.86-3.40, the absorption of the system exceeds 98% across 680-1,033 nm. In seawater with optimized dielectric constant, ≥94% light absorption over 400-1,200 nm can be achieved; particularly in the wavelength range of 480-960 nm and dielectric-constant range of 0.82-3.50, the absorption is greater than 98%. In an environment with even higher refractive index (1.74), ≥98% light absorption over 400-1,200 nm can be achieved, giving better performance. The influence of angle of incidence on light absorption of the MIM system is also analyzed, and the angle tolerance for ≥90% broadband absorption of a TM wave is up to 40° in an environment with large refractive index. While the incident-angle dependence of the absorption of a TE wave is nearly the same for different circumstances, the situation is different for a TM wave.

• Journal of the Korean Wood Science and Technology
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• 제13권3호
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• pp.49-53
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• 1985

The effects of pre-treatments, the hot water extraction of wood meal and the addition of chemical ($CaCl_2$) to wood-cement water system on the properties of wood-cement composite such as modulus of rupture (MOR), modulus of elasticity (MOE), water sorption ratio and swelling ratio of resulting boards were studied in this experiment. The wood meals through 0.83mm(20 mesh) and retained on 0.42mm(35 mesh) screen were prepared from Pinus densiflora S. at Z. and Larix leptolepsis G. For hot water extraction, 500 grams of wood meal for each species were heated to boiling with 1,500ml of distilled water in 2-liter beaker for 6 hours. Every 2 hours, the wood meals were washed with boiling distil1ed water and reheated to boiling again. After 6 hours boiling, the boiled wood particles were collected by pouring this particles on 200 mesh screen. The collected particles then washed twice with hot distilled water and dried for 24 hours in an oven at $109{\pm}20^{\circ}C$. A mixture of 663.4 grams of cement with 331.7 grams of wood meal based on oven-dry weight were dry-mixed in a plastic vessel. The mixture was kneaded with 497.6ml of distilled water in the ratio of 1.5ml of water to a gram of wood meal. To add calcium chloride to the mixture as an accelerator, $CaCl_2$ 4% solution by weight per volume, was added to pine-or larch-cement board in the ratio of 3% to cement weight. To set wood-cement board, this mixture was clamped at 30cm ${\times}$ 30cm, in thickness of 1.5cm for 3 days at room temperature, declamped and then placed at open condition for 17 days. The target density was 1.0. The four specimens sized to 5cm in width and 28cm in length were used for MOR and MOE test for each treatment. After MOR test, the tested specimens were cut to the size of 5cm ${\times}$ 5cm for water sorption and swelling test. The twenty specimens used to measure the water sorption ratio (soaking 24 hours) and ten of these were used for swelling ratio measurement The results obtained were as follows: 1) Larch was not suitable for wood-cement boards because larch-cement board developed no strength, but pine showed 97.9kg/$cm^2$ by hot water extraction. 2) To increase MOR, hot water extraction was more effective than the addition of $CaCl_2$ in pine and larch because the $CaCl_2$ addition was seemed to speed up the ratio of cement hydration without reacting with the wood substances. 3) The water sorption ratio was lowered by the addition of $CaCl_2$ to wood-cement system because the chemical additive accelerated the rate of cement hydration. 4) In pine-cement board, the swelling ratio from 0.37 to 0.42 percent was observed in length and the swelling ratio from 0.88 to 2.0 percent in thickness. As a rule, the swelling ratio of wood-cement board was very low and the swelling ratio in thickness was higher than in length.

• 한국농공학회논문집
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• 제62권4호
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• pp.99-110
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• 2020

The objective of this study is to analyze the trend of changes in the water circulation rates under climate change by adopting the concept of WCR defined by the Ministry of Environment. With the need for sound water circulation recovery, the MOE proposed the idea of WCR as (1-direct flow/precipitation). The guideline for calculating WCR suggests the SCS method, which is only suitable for short term rainfall events. However, climate change, which affects WCR significantly, is a global phenomenon and happens gradually over a long period. Therefore, long-term trends in WCRs should also be considered when analyzing changes in WCR due to climate change. RCP (Representative Concentration Pathway) 4.5 and 8.5 scenarios were used to simulate future runoff. SWAT (Soil and Water Assessment Tool) was run under the future daily data from GCMs (General Circulation Models) after the calibration. In 2085s, monthly WCR decreased by 4.2-9.9% and 3.3-8.7% in April and October. However, the WCR in the winter increased as the precipitation during the winter decreased compared to the baseline. In the aspect of yearly WCR, the value showed a decrease in most GCMs in the mid-long future. In particular, in the case of the RCP 8.5 scenario, the WCR reduced 2-3 times rapidly than the RCP 4.5 scenario. The WCR of 2055s did not significantly differ from the 2025s, but the value declined by 0.6-2.8% at 2085s.

• 한국지리정보학회지
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• 제5권3호
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• pp.87-98
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• 2002

광주 전남의 상수원인 주암호 유역에 대해 GIS를 이용하여 점오염원과 비점오염원 부하량을 산정하였으며 기 개발된 모형을 이용하여 수질을 모의하였다. 점오염원 부하량은 환경부에서 발표한 원단위(1998)를 이용하여 산정하였고, 비점오염원 부하량은 유출곡선지수를 이용한 SCS방법으로 직접유출량을 계산한 후 우리나라 유역의 특성에 맞는 토지이용별 기대평균농도 값을 이용하여 산정하였다. 수질모의는 미국환경청에서 개발한 WASP모형(2001)을 이용하였으며 대상유역을 GIS를 이용하여 경사, 방향, 고도, 토양, 토지이용과 강우량에 따라 44개의 소유역으로 구분하고, 그중 하나의 소유역에 대해 모형을 적용하였다. 모형의 결과치를 수질관측치와 비교한 결과 매우 유사함을 알 수 있었다.

• 문화기술의 융합
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• 제10권2호
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• pp.67-71
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• 2024

莫友芝(모유지)(1811-1871)는 청나라 말기의 저명한 학자, 시인, 서예가이다. 모유지는 일생 동안 경력이 풍부하고 시야가 넓으며 특히 증국 번 막부에 들어간 10년 동안 많은 정치, 문화 엘리트를 사귀었다. 모유지는 총명하고 부지런하며 학문에 열중했으며 당시 각계각층의 유명인들과 교유할 수 있는 기회가 있어 재능을 충분히 발휘했다. 청대에는 금석학이 전례 없이 번영했고, 서예에서는 비학(碑學)이 서단의 절대적인 주도가 되었으며, 전예서는 진한(汉漢) 이후 처음으로 크게 번영하였다. 시대에 순응한 모유지는 학문에 몰두하고 한묵을 돌보며 자신만의 서예의 길을 걷는것이 사실이다. 그의 글씨 중 전서, 예서, 해서, 행, 특히 전서 예서가 정교하다. 본 고는 예서를 바탕으로 전형적인 풍격과 비정형 형태을 각각 설명하고 예서와 다른 서체 간의 관계에 대해서도 간략하게 논의한다. 마지막으로 당대 예서 창작에 대한 예서의 참고 의의를 간략하게 요약하였다. 논술 과정에서 서예를 근거로 관련 문헌을 탐독하고 모유지의 인생 경험을 결합하여 객관적이게 진술하였다.

• 한국시뮬레이션학회논문지
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• 제24권3호
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• pp.77-87
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• 2015

국방 M&S(Modeling & Simulation) 분야는 컴퓨터상에 모의 전장 환경 및 무기 모델을 구축하고 다양한 시나리오에 의해 시뮬레이션을 수행하여 무기체계의 효과도를 분석하는 현실적인 수단으로 이용되고 있다. 그러나, 무기체계의 구조 및 행위가 복잡해짐에 따라 이를 시뮬레이션 모델로 만드는 과정이 어려워지고 있다. 모델 재사용 저장소는 시뮬레이션 모델 구축에 필요한 비용을 절감하기 위해 기존에 개발 및 검증된 모델을 저장하고 있다. 그러나 기존의 재사용 저장소들은 특정 플랫폼 및 환경에서만 운용되어 사용자 층에 제한이 있으며, 보안 및 무중단 서비스를 위한 메커니즘이 미흡하여 무기체계 모델과 같은 보안 및 신뢰성이 필요한 모델을 저장하기에는 한계가 있다. 본 논문에서는 무기체계 모델의 재사용을 장려하기 위한 클라우드 저장소인 W-Cloud (Weapon Cloud)를 구축하여 다양한 플랫폼 및 환경에서 활용될 수 있도록 하였다. 또한, 계층형 정보보호 및 기밀성 보장을 통해 무기 모델의 재사용 과정에서 생길 수 있는 보안상의 문제를 효과적으로 해결할 수 있도록 하였다.