• 한국지하수토양환경학회지:지하수토양환경
• /
• 제18권3호
• /
• pp.52-57
• /
• 2013

Radon, which is one of the radioactive elements in the natural world, exists in the atmosphere and water. When this element inflows into the human body, it carries the risks of developing lung cancer and stomach cancer. Therefore, in this study, an effective 10 L scaled reactor was produced to mitigate radon in water and the radon mitigation efficiency in water following the changes in water temperature and amount of aeration were evaluated. Based on this, the radon mitigation efficiency (SRRR; Specific radon removal rate) was derived per unit air volume. According to the study result, when water temperature increased from $10^{\circ}C$ to $16^{\circ}C$, the SRRR value increased from 95 $nCi/m^3{\cdot}L$ to 134.4 $nCi/m^3{\cdot}L$, and when the amount of aeration increased from 0.2 L/min to 1 L/min, the SRRR value decreased from 198.1 $nCi/m^3{\cdot}L$ to 72.2 $nCi/m^3{\cdot}L$. Therefore, based on the experimental results, it is considered that it can be applied as a examination factor and objective indicator during the design of future radon-in-water mitigation systems.

• 멤브레인
• /
• 제12권4호
• /
• pp.226-239
• /
• 2002

유기용매의 탈수화 공정의 거동을 예측할 수 있는 투과증발 판틀형 모듈에 대한 전산모사 모델을 확립하였는데 이는 공정의 분석 및 최적화의 도구로 사용할 수 있다. 확립한 모델은 물질, 열 및 농도 수지식으로 이루어졌으며 유한요소법의 수치해석을 사용하여 각 투과 특성들은 계산하였다. 본 전산모사에서는 모듈내 각 두개의 막 사이에 있는 단일 공급유로를 기본 미분단위부피로 사용함으로써 계산과정을 단순화하초 계산시간을 단축할 수가 있었다. 또한 모델식에 각 파라메타들을 실제 공정에서 직접 구하여 사용함으로써 공정모사의 정확성을 얻을 수가 있었다. 모사모델의 타당성을 화인하기 위해서 에탄올/물 혼합물을 모델 혼합물로 선정하여 상업 투과막인 $AzeoSep^{TM}$-2002를 통한 투과실험을 행하여 각 투과 특성들을 얻었으며 얻은 이들 값들과 모사 모델식으로부터 계산된 값들과 비교한 결과 서로 잘 일치함을 보여 본 모사모델의 타당성을 입증하였다. 또한 모사모델을 사용하여 연속식 및 회분식 투과공정에서의 에탄을 탈수 공정을 모사하였는데 모사 결과들은 공정 분석 및 최적화를 위한 기본자료로 활용할 수 있다. 본 연구에서는 모사결과를 토대로 회분식 공정과 연속식 공정을 비교 분석하였다.

• 한국초등과학교육학회지:초등과학교육
• /
• 제36권1호
• /
• pp.31-42
• /
• 2017

This study aimed to investigate the effect of science class using multiple intelligence on science learning motivation, academic achievement and science process skill of elementary student. The number of participants were 98, 4 classes of $3^{rd}$ graders in G elementary school in B city. The experimental group, 2 classes including 49 participants, had science classes using multiple intelligence while the comparative group, 2 classes including 49 participants, took ordinary teacher-driven lessons using teacher's guidebook. Pre and post tests were done before and after executing lessons to assess the changing in each group's science learning motivation, academic achievement and science process skill. The results of this study can be summarized as follows: First, the pre and post test results of science learning motivation revealed that the experimental group had higher improvement compared to the comparative group and the difference was meaningful. Second, the post test results of the science academic achievement showed that the experimental group had higher average value compared to the comparative group and the difference was meaningful. Third, the pre and post test results of basic science process skill showed that the experimental group had higher average value compared to the comparative group and the difference was meaningful, especially in inference and prediction elements.

• 한국실내디자인학회논문집
• /
• 제25권6호
• /
• pp.3-14
• /
• 2016

According to Plato's ontology, we lead our lives by establishing a relationship with others in the society. However in rapidly changing era, our lives was gradually moving towards personal tendency. Even for the relationship with family, not with others. Thus, awareness about owning properties has changed due to the sociocultural factors and increase number of single-person households. So in this study, the considerations for single-person housing were perceived through preceding research, and the elements making spatial boundary of shared housing were drawn to make rational space sharing based on the boundary with others and of the living environment. With overall analysis based on the spatial boundary features of planned shared housing, the plan characteristics according to the spatial boundary of the current shared housing is to be drawn and analyzed. Third, The expressive and structural features of spatial boundary as above appear with mutual flexible connectivity, And the result shows that the modularity was the highest. Among them variable coupling modularity of shows how it is possible to combine efficiently and variously the private and public spaces with regularity of 'space of optimal unit'. This study drew plan characteristics from more detailed space border of shared housing. Therefore, The basic framework of the characteristics spin for the cases that newly emerge later on.

• 한국작물학회지
• /
• 제44권3호
• /
• pp.225-229
• /
• 1999

Unstable seedling stand establishment of wet direct seeding culture of rice is one of the major elements preventing the extension of its culture area. In order to develop methods of seedling stand improvement in direct seeded rice on flooded surfaces, three field experiments were conducted on silty loam soil using a cultivar 'Donjinbyeo' for three years, mainly focusing on water management after seeding and seed soaking with plant growth regulators (PGRs). Under the condition of shallow flooding after seeding, seedling stand rate increased and floating seedling rate decreased in both early and normal season seeding compared to deep flooding. With earlier draining time after seeding, there was a tendency towards preferential growth of the seminal root, increase of seedling stand and decrease of the floating seedling rate. Therefore the highest seedling numbers per unit area and the lowest floating seedling numbers were found upon drainage at 1 day after seeding (DAS), while a contrary tendency was shown upon conventional drainage at 7 DAS. Seed soaking with PGRs such as Metalaxyl or mixing of Metalaxyl with gibberellic acid (GA$_3$) significantly increased the seedling stand. In addition the effects of PGR treatment on seedling stand and the early growth of plants were greater under flooded conditions than under drained conditions after seeding, although draining of water after seeding improved the seedling establishment rate more when compared with the PGR treatment. These results suggest that draining management after seeding or maintaining of shallow flooding for a week is the most effective method to improve the seedling stand rate in wet direct seeding.

• 한국초지조사료학회지
• /
• 제16권1호
• /
• pp.27-38
• /
• 1996

This study was conducted to evaluate the potential of Festulolium braunii(Festuca pratensis Huds. $\times$ Loliurn mulrijZorum Lam.)as forge sources. The experiment was arranged in a split plot design with four replications from Feb. 1995. to Jan. 1996 at Hohenheim university. Main plots consisted of three forage species, Festulolirtrn braunii(Paulita), Lolium multiJomm(Lemtla), and Secale cereale(Halo) and subplots consisted of three maturity, boot, heading, and anthesis. The growth characteristics, DM yields, nutritive value, N and energy balance were observed. The heading date of Festulolium braunii was about two days earlier than that of Loliunz mrtltiflorum, farthermore Fesrulolium braunii retained higher leaf weight ratio(LWR) than other species. Festulolium brarrnii failed to show any significant differences in grass length, number of tillers, LAI, CGR, and DM accumulation when harvested at the same stage of maturity as compare with Loliurn mulriiflorutn or Setale cerede, bur the content of CP, OMD, and mineral elements and NEL value of Festulolium braunii compare to othes were slightly increased(P<0.05), while the content of NDF, ADF, and lignin decreased(P<0.05). The yield of CP was greater for Festulolium braunii than for Lolium multfimm and yields of DOM and NEL per unit area(ha) for Festulolium braunii were greater than for other species(P<0.05). The equivalent or higher DM production and nutritive value are obtained when Festulolium braunii are cut during the period from boot to anthesis stages, therefor DM intake, preference, and N and energy balance were also higher for Festulolirtm braunii compare to for other species. It could be suggested that Lolium multrfirum would be a more suitable substitute to Festuloliron braunii without decreasing forage production and quality, but the substitutive effect of Secale cereale would be difficult because of the maor differences in growth type and period compare to Fesrulolium braunii. From above the results of this experiment it appears that Festulolium braunii have a potential to provide forage sources. but funher research is needed to ascertain their potential under the climate of Korea.

• Advances in Energy Research
• /
• 제7권1호
• /
• pp.1-19
• /
• 2020

Energy consumption of air-conditioning and refrigeration systems is responsible for about 25 to 30% of the energy demand especially in hot seasons. This equipment is mostly electricity dependent and their use in principle affects negatively the environment. Enhancing the energy efficiency of the existing equipment is important as one of the measures to reduce environment impacts. This paper reports the results of an experimental study to evaluate the impacts of the use electronic expansion valve and variable velocity compressor on the performance of vapor compression refrigeration system. The experimental rig is composed of two independent circuits one for the vapor compression system and the other is the secondary fluid system. The vapor compression system is composed of a forced air condenser unit, evaporator, hermetic compressor and expansion elements, while the secondary system has a pump for circulating the secondary fluid, and an air conditioning heat exchanger. The manufacturer's data was used to determine the optimal points of operation of the system and consequently tests were done to evaluate the influence of variation of the compressor velocity and the opening of the expansion device on the performance of the refrigeration system. A fuzzy logic model was developed to control the rotational velocity of the compressor and the thermal load. Fuzzy control model was made in LabVIEW software with the objective of improving the system performance, stability and energy saving. The results showed that the use of fuzzy logic as a form of control strategy resulted in a better energy efficiency.

• 한국위성정보통신학회논문지
• /
• 제7권3호
• /
• pp.86-93
• /
• 2012

본 논문에서는 시맨틱 웹에서 온톨로지와 메타데이터를 기술하는 OWL 문서를 대상으로 하는 키워드 검색 기법과 랭킹 기법을 제안한다. 제안한 키워드 검색 기법은 OWL 문서에 대한 키워드 검색 결과의 단위를 정보 리소스로 정의하고 질의 키워드의 범위를 클래스와 프로퍼티의 이름은 물론 리터럴 데이터까지 확장하였다. 그리고 클래스나 프로퍼티의 계층 관계, 동등 관계 등 OWL 문서에 정의되어 있는 기본적인 추론 요소들을 고려하여 직접 기술되어 있지 않지만 새롭게 유도되는 정보도 키워드 검색에 반영하였다. 또한 키워드를 통해 간접적으로 의미적 관계를 맺고 있는 정보 리소스에 대한 검색이 가능하기 때문에 질의 키워드와 관련이 있는 많은 수의 정보 리소스들을 검색할 수 있다. 제안한 랭킹 기법은 OWL 문서의 특성을 고려하여 다양한 요소를 순위 결정에 참여시킴으로써 사용자의 검색 만족도를 높일 수 있다. 본 논문에서 제안한 키워드 검색 기법과 랭킹 기법은 방송 프로그램과 같은 디지털 콘텐츠의 검색 등 다양한 분야에서 활용될 수 있다.

• 한국콘텐츠학회논문지
• /
• 제9권11호
• /
• pp.289-296
• /
• 2009

본 논문에서, 생물계로 자기자극장치를 사용할 경우 잠재적인 사용에 대한 전력소자 응용제어 기술에 대해 언급 하고자 한다. 자기자극장치의 효과는 자기 자극코일에 의해 전달된 전류 펄스파형에 유도한 전계와 기하학 구성에 의존한다. TMS는 두뇌에 있는 전계를 유도하는 전자장의 펄스를 머리의 외부에서 자극하게 된다. TMS는 두뇌의 자극을 통해, 진단 및 치료에 있는 수많은 응용이 가능하다. 이러한 요소들은 코일의 구성과 전원 장치와 크기의 등가적 요구와 특성으로 매우 중요한 기능을 가지게 된다. 제안하고자 하는 해결방법은 입력에 대하여 가변크기와 주기를 가지는 전류펄스 발생을 가진다. 또한, 해결방법은 전원에서 부하로 에너지 전송과 축적의 요소를 기본으로 할 수가 있다. 제안한 방식으로, 전력 회로 매개 변수의 충분한 통제를 통한 기획과 전략으로 단극파형 또는 양극 파형을 얻을 수가 있었다.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
• /
• 제16권7호
• /
• pp.775-787
• /
• 2010

GPU(Graphics Processing Unit)는 범용 CPU와는 달리 다수코어 스트리밍 프로세서(manycore streaming processor) 형태로 특화되어 발전되어 왔으며, 최근 뛰어난 병렬 처리 연산 능력으로 인하여 점차 많은 영역에서 CPU의 역할을 대체하고 있다. 이러한 추세에 따라 최근 NVIDIA 사에서는 GPGPU(General Purpose GPU) 아키텍처인 CUDA(Compute Unified Device Architecture)를 발표하여 보다 유연한 GPU 프로그래밍 환경을 제공하고 있다. 일반적으로 CUDA API를 사용한 프로그래밍 작업시 GPU의 계산구조에 관한 여러 가지 요소들에 대한 특성을 정확히 파악해야 효율적인 병렬 소프트웨어를 개발할 수 있다. 본 논문에서는 다양한 실험과 시행착오를 통하여 획득한 CUDA 프로그래밍에 관한 최적화 기법에 대하여 설명하고, 그러한 방법들이 프로그램 수행의 효율에 어떠한 영향을 미치는지 알아본다. 특히 특정 예제 문제에 대하여 효과적인 계층 구조 메모리의 접근과 코어 활성화 비율(occupancy), 지연 감춤(latency hiding) 등과 같이 성능에 영향을 미치는 몇 가지 규칙을 실험을 통해 분석해봄으로써, 향후 CUDA를 기반으로 하는 효과적인 병렬 프로그래밍에 유용하게 활용할 수 있는 구체적인 방안을 제시한다.