• Title/Summary/Keyword: characteristics of space and use

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Study of NO Storage and Reduction on LNT by Micro Bench-Flow Reactor (마이크로 벤치-플로우 리액터를 이용한 LNT 촉매의 NO 흡장과 정화성능에 관한 연구)

  • Yoon, Joo-Wung;Hwang, Seung-Kwon;Hwang, In-Goo;Park, Sim-Soo;Lee, Jin-Ha;Yeo, Gwon-Koo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.8
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    • pp.789-798
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    • 2011
  • We carry out an experimental investigation to analyze the basic performance of NO(nitric oxide) storage in a lean phase and also analyze the NO reduction achieved by the spraying of reducing agents in the rich phase of the exhaust gas in an LNT(Lean NOx Trap). This is an after-treatment system used to reduce the NOx emissions from a diesel engine. If the stored NO is reduced, we measure the outlet concentration downstream of the LNT. The test LNT material used in the experiments is commercial LNT. After being canned into stainless-steel(SUS304), it was built in a micro bench-flow reactor. Compositions of feed gases, three heated and three no heated gases were sprayed upstream of the LNT to analyze the characteristics. We use various temperatures and space velocities as response variables.

Pull-out Strength Characteristics of Revegetation Species Root used for Forest Road Slope (임도사면 녹화식물뿌리의 인발강도특성에 관한 연구)

  • Ji, Byoung Yun;Jung, Do Hyun;Chun, Kwon Suk;Kim, Jong Yoon
    • Journal of Korean Society of Forest Science
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    • v.95 no.1
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    • pp.45-49
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    • 2006
  • The objective of this study is to offer a basic information to select the plant species for environmentally friendly forest road by quantifying the pull-out strength by 18 species used for a revegetation of forest road slope. In the investigation of the root depth growth during 17 months, Indigobush amorpha showed maximum depth of 34.0 cm and perennial ryegrass showed minimum depth of 17.7 cm among all species. The pull-out strength by herb species was $0.054ton/m^2/plant$ for exotic species, $0.085ton/m^2/plant$ for indigenous species, and by shrub species was $0.049ton/m^2/plant$. There were no large difference among herb species in pull-out strength, but shrub species were approximately 9 times stronger than herb species. Thus, for maximizing tightening effect and use of inner soil space. The mixed seeding using herb for erosion control and shrub for shallow failure protection would make up optimal revegetation of forest road slope.

A Characteristics of Cultural Heritage Landscaping of Jeongnimsa Temple Site in Buyeo from Perspective of Maintenance Project (정비사업을 통해 본 부여 정림사지 문화재 조경의 특성)

  • Kim, Mi-Jin;So, Hyun-Su
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.39 no.4
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    • pp.38-49
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    • 2021
  • The maintenance project of the Jeonglimsa temple site started with the objective of restoring the original structure of the temple, however, it was gradually transitioned to a landscaping maintenance project over time that constructs a landscape of the temple area. With paying attention to these facts, this study summarized the characteristics of cultural heritage landscaping of the Jeonglimsa temple site as follows. First, Cultural heritage landscaping is a landscaping act that creates, maintains, and manages landscapes within the spatial scope of the cultural heritage designated under the Cultural Heritage Protection Act and the cultural heritage protection area established around it. It is a work that includes protection and maintenance of the excavated remains, spaces by each function and plans for moving lines, Installation of structures to protect cultural properties, adoption of the facilities and structures for convenience of visitors, and construction of vegetation landscape. Second, the cultural heritage landscaping of the Jeonglimsa temple site has been developed in 5 periods, and these include 'the period of historical site investigation' that the temple name was identified through the designation of cultural assets and excavation investigation by the Japanese rule, 'the construction period of Baekje Tower Park' after the liberation from the Japanese rule, 'the period of Baekje Cultural Area Development Project' designated as a historical site, 'the period of the Comprehensive Development Project for a Specific Area of Baekje Culture',which was proceeded with the establishment of the park and museum instead of restoring the temple building due to the difficulty in gathering the pieces of historical evidence, and 'the period of the Jeonglimsa temple site restoring project', which was designated as a World Heritage Site while restoring the buildings deployment in the Buddhist temple at the time of foundation era of Baekje Dynasty. Third, this study verified the landscape changes of the Jeonglimsa temple site that have been transitioned, for instance, the creation of a commemorative park linked to the outer garden of Buyeo Shrine, the implementation of urban planning of the Japanese colonial era, the creation of a protective environment for the excavated historical structures and temple area, the restoration of building deployment in the Buddhist temple, and the sincerity restoration and utilization of cultural assets. Fourth, the landscape of Jeongnimsa temple site is determined by the subject and scope of cultural property designation, land use, movement lines and pavement, repairing methods of remains, structures, facilities, and vegetation. The characteristics of the cultural heritage landscape of Jeongnimsa Temple were derived, such as creating a procedural landscape considering the expansion of the cultural heritage designation scope, securing authenticity by maintaining relics in consideration of reversibility, creating a vegetative landscape suitable for historical and cultural landscapes, and enhancing the value of cultural heritage enjoyment by providing an open space.

Performance Comparison of Clustering using Discritization Algorithm (이산화 알고리즘을 이용한 계층적 클러스터링의 실험적 성능 평가)

  • Won, Jae Kang;Lee, Jeong Chan;Jung, Yong Gyu;Lee, Young Ho
    • Journal of Service Research and Studies
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    • v.3 no.2
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    • pp.53-60
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    • 2013
  • Datamining from the large data in the form of various techniques for obtaining information have been developed. In recent years one of the most sought areas of pattern recognition and machine learning method is created with most of existing learning algorithms based on categorical attributes to a rule or decision model. However, the real-world data, it may consist of numeric attributes in many cases. In addition it contains attributes with numerical values to the normal categorical attribute. In this case, therefore, it is required processes in order to use the data to learn an appropriate value for the type attribute. In this paper, the domain of the numeric attributes are divided into several segments using learning algorithm techniques of discritization. It is described Clustering with other data mining techniques. Large amount of first cluster with characteristics is similar records from the database into smaller groups that split multiple given finite patterns in the pattern space. It is close to each other of a set of patterns that together make up a bunch. Among the set without specifying a particular category in a given data by extracting a pattern. It will be described similar grouping of data clustering technique to classify the data.

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Effect of Co-catalyst CeO2 on NOx Reduction in PtNi/W-TiO2 Catalysts for Low-temperature H2-SCR (저온 H2-SCR용 PtNi/W-TiO2 촉매에 조촉매 CeO2가 NOx 저감에 미치는 영향)

  • Jungsoo Kim;Younghee Kim
    • Clean Technology
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    • v.29 no.4
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    • pp.313-320
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    • 2023
  • In order to increase the usability of H2-SCR, the NOx removal characteristics with catalyst powder of PtNi/CeO2-W-TiO2 using Ce as a co-catalyst was synthesized and coated on a porous metal structure (PMS) were evaluated. Catalyst powder of PtNi/CeO2-W-TiO2(PtNi nanoparticles onto W-TiO2, with the incorporation of ceria (CeO2) as a co-catalysts) was synthesized and coated onto a porous metal structure (PMS) to produce a Selective Catalytic Reduction (SCR) catalyst. H2-SCR with CeO2 as a co-catalyst exhibited higher NOx removal efficiency compared to H2-SCR without CeO2. Particularly, at a 10wt% CeO2 loading ratio, the NOx removal efficiency was highest at 90℃. As the amount of catalyst coating on PMS increased, the NOx removal efficiency was improved below 90℃, but it was decreased above 120℃. When the space velocity was changed from 4,000 h-1 to 20,000 h-1, the NOx removal efficiency improved at temperatures above 120℃. It was expected that the use of the catalyst could be reduced by applying the PMS with excellent specific surface area as a support.

Analysis of Changes in Forest According to Urban Expansion Pattern and Morphological Features - Focused on Seoul and Daegu - (도시의 공간 확장 및 형태적 특징에 따른 산림녹지의 변화 분석 - 서울, 대구를 중심으로 -)

  • Ryu, Jieun;Hwang, Jinhoo;Lee, Junhee;Chung, Hye-In;Lee, Kyung-il;Choi, Yu-Young;Zhu, Yongyan;Sung, Min-Jun;Jang, Raeik;Sung, Hyun-Chan;Jeon, Seongwoo;Kang, Jin-Yung
    • Korean Journal of Remote Sensing
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    • v.33 no.5_3
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    • pp.835-854
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    • 2017
  • Government regulations and policies are important means of restraining the indiscreet expansion of urban areas. According to the standards from those means, it is clear that the fluctuation of forest green proportion encroached by the increase of urban space is obvious. In this study, we interpreted the changes of urban areas as well as the green ones owing to the urban expansion by the decades from 1996, with focusing on the cities of Seoul and Daegu highly developed in South Korea. The purpose of this study is to analyze the spatial expansion and morphological characteristics of urban land cover using not only satellite imageries (1996, 2006, 2016). but also the urban expansion intensity index (UEII) and GUIDOS program. Ultimately, this study is to compare the changes in the rate of forests due to urban expansions annually analyzed based on areas of forest elevation, slope, and the area of single forest patch. In Seoul, the expansion begun from urban space to suburban areas was comparatively rapid, which led the forest fragmentation and the gradual decline of the single patch. However, when it comes to DEM (Digital elevation model) and slope above a certain standard, by the development regulations, there was little decrease in area by anthropogenic developments. The city of Daegu has increased at a slow speed since 1996 in urban and suburban areas, whereas green forests have greatly increased through green forest conservation campaigns. In this way, as to the government policies and regulations, the quantitative and morphological expansion of cities owing to development could be controlled and forest spaces could be preserved as well. Therefore, regulations and policies by the government should be appropriately utilized for sustainable cities.

Some New Problems of International Aviation Security- Considerations Forcused on its Legal Aspects (최근국제항공보안대책(最近國際航空保安対策)의 제간제(諸間題) -특히 법적측면(法的測面)을 중심(中心)으로-)

  • Choi, Wan-Sik
    • The Korean Journal of Air & Space Law and Policy
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    • v.5
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    • pp.53-75
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    • 1993
  • This article is concerned with the comment on "Some New Problems of International Aviation Security-Considerations Forcused on its Legal Aspects". Ever since 1970, in addition to the problem of failure to accept the Tokyo, Hague and Montreal Conventions, there has been also the problem of parties to them, failing to comply with their obligations under the respective treaties, in the form especially of nominal penalties or the lack of any effort to prosecute after blank refusals to extradite. There have also been cases of prolonged detention of aircraft, passengers and hostages. In this regard, all three conventions contain identical clauses which submit disputes between two or more contracting States concerning the interpretation or application of the respective conventions to arbitration or failing agreement on the organization of the arbitration, to the International Court of Justice. To the extent to which contracting States have not contracted out of this undertaking, as I fear they are expressly allowed to do, this promision can be used by contracting States to ensure compliance. But to date, this avenue does not appear to have been used. From this point of view, it may be worth mentioning that there appears to be an alarming trend towards the view that the defeat of terrorism is such an overriding imperative that all means of doing so become, in international law, automatically lawful. In addition, in as far as aviation security is concerned, as in fact it has long been suggested, what is required is the "application of the strictest security measures by all concerned."In this regard, mention should be made of Annex 17 to the Chicago Convention on Security-Safeguarding International Civil Aviation against Acts of Unlawful Intereference. ICAO has, moreover, compiled, for restricted distribution, a Security Manual for Safeguarding Civil Aviation Against Acts of Unlawful Interference, which is highly useful. In this regard, it may well be argued that, unless States members of ICAO notify the ICAO Council of their inability to comply with opecific standards in Annex 17 or any of the related Annexes in accordance with Article 38 of the 1944 Chicago Convention on International Civil Aviation, their failure to do so can involve State responsibility and, if damage were to insure, their liability. The same applies to breaches of any other treaty obligation. I hope to demonstrate that although modes of international violence may change, their underlying characteristics remain broadly similar, necessitating not simply the adoption of an adequate body of domestic legislation, firm in its content and fairly administered, but also an international network of communication, of cooperation and of coordination of policies. Afurther legal instrument is now being developed by the Legal Committee of ICAO with respect to unlawful acts at International airports. These instruments, however, are not very effective, because of the absence of universal acceptance and the deficiency I have already pointed out. Therefore, States, airports and international airlines have to concentrate on prevention. If the development of policies is important at the international level, it is equally important in the domestic setting. For example, the recent experiences of France have prompted many changes in the State's legislation and in its policies towards terrorism, with higher penalties for terrorist offences and incentives which encourage accused terrorists to pass informations to the authorities. And our government has to tighten furthermore security measures. Particularly, in the case an unarmed hijacker who boards having no instrument in his possession with which to promote the hoax, a plaintiff-passenger would be hard-pressed to show that the airline was negligent in screening the hijacker prior to boarding. In light of the airline's duty to exercise a high degree of care to provide for the safety of all the passengers on board, an acquiescence to a hijacker's demands on the part of the air carrier could constitute a breach of duty only when it is clearly shown that the carrier's employees knew or plainly should have known that the hijacker was unarmed. The general opinion is that the legal oystem could be sufficient, provided that the political will is there to use and apply it effectively. All agreed that the main responsibility for security has to be borne by the governments. A state that supports aviation terrorism is responsible for violation of International Aviation Law. Generally speaking, terrorism is a violation of international law. It violates the sovereign rights of states, and the human rights of the individuals. We have to contribute more to the creation of a general consensus amongst all states about the need to combat the threat of aviation terrorism. I think that aviation terrorism as becoming an ever more serious issue, has to be solved by internationally agreed and closely co - ordinated measures.

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Dynamic Characteristics of Liquidity Filling Materials Mixed with Reclaimed Ash (매립석탄회를 혼합한 유동성 충진재의 동적거동특성)

  • Chae, Deokho;Kim, Kyoungo;Shin, Hyunyoung;Cho, Wanjei
    • Journal of the Korean GEO-environmental Society
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    • v.15 no.4
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    • pp.5-11
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    • 2014
  • Recently, there have been various lifeline installations constructed in the underground space of urban area due to the effective use of land. For newly installed lifelines or the management of the installed lifelines, many construction activities of excavation and backfilling are observed. Around these area, there are possibilities of collapse or excessive settlement due to the leaking of the pipe or unsatisfactory compaction of backfill material. Besides, construction costs can be saved since the on-site soils are used. The application of this liquidity filling material is not only to the lifeline installation but also to underpin the foundation under the vibrating machinery. On the evaluation of the applicability of this method to this circumstance, the strength should be investigated against the static load from the machine load as well as the vibration load from the activation of the machine. In this study, the applicability of the liquidity fill material on the foundation under the vibrating machinery is assessed via uniaxial compression and resonant column tests. The liquidity filling material consisting of the on-site soils with loess and kaolinite are tested to investigate the static and dynamic characteristics. Furthermore, the applicability of the reclaimed ash categorized as an industrial waste is evaluated for the recycle of the waste to the construction materials. The experimental results show that the shear modulus and 7 day uniaxial strength of the liquidity filling material mixed with reclaimed ash show higher than those with the on-site soils. However, the damping ratio does not show any tendency on the mixed materials.

A study on performance evaluation of fiber reinforced concrete using PET fiber reinforcement (PET 섬유 보강재를 사용한 섬유 보강 콘크리트의 성능 평가에 관한 연구)

  • Ri-On Oh;Yong-Sun Ryu;Chan-Gi Park;Sung-Ki Park
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.25 no.4
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    • pp.261-283
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    • 2023
  • This study aimed to review the performance stability of PET (Polyethylene terephthalate) fiber reinforcing materials among the synthetic fiber types for which the application of performance reinforcing materials to fiber-reinforced concrete is being reviewed by examining short-term and long-term performance changes. To this end, the residual performance was analyzed after exposing the PET fiber to an acid/alkali environment, and the flexural strength and equivalent flexural strength of the PET fiber-reinforced concrete mixture by age were analyzed, and the surface of the PET fiber collected from the concrete specimen was examined using a scanning microscope (SEM). The changes in were analyzed. As a result of the acid/alkali environment exposure test of PET fiber, the strength retention rate was 83.4~96.4% in acidic environment and 42.4~97.9% in alkaline environment. It was confirmed that the strength retention rate of the fiber itself significantly decreased when exposed to high-temperature strong alkali conditions, and the strength retention rate increased in the finished yarn coated with epoxy. In the test results of the flexural strength and equivalent flexural strength of the PET fiber-reinforced concrete mixture, no reduction in flexural strength was found, and the equivalent flexural strength result also did not show any degradation in performance as a fiber reinforcement. Even in the SEM analysis results, no surface damage or cross-sectional change of the PET reinforcing fibers was observed. These results mean that no damage or cross-section reduction of PET reinforcing fibers occurs in cement concrete environments even when fiber-reinforced concrete is exposed to high temperatures in the early stage or depending on age, and the strength of PET fibers decreases in cement concrete environments. The impact is judged to be of no concern. As the flexural strength and equivalent flexural strength according to age were also stably expressed, it could be seen that performance degradation due to hydrolysis, which is a concern due to the use of PET fiber reinforcing materials, did not occur, and it was confirmed that stable residual strength retention characteristics were exhibited.

Quantitative evaluation of collapse hazard levels of tunnel faces by interlinked consideration of face mapping, design and construction data: focused on adaptive weights (막장관찰 및 설계/시공자료가 연계 고려된 터널막장 붕괴 위험도의 정량적 산정: 가변형 가중치 중심으로)

  • Shin, Hyu-Soung;Lee, Seung-Soo;Kim, Kwang-Yeom;Bae, Gyu-Jin
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.15 no.5
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    • pp.505-522
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    • 2013
  • Previously, a new concept of indexing methodology has been proposed for quantitative assessment of tunnel collapse hazard level at each tunnel face with respect to the given geological data, design condition and the corresponding construction activity (Shin et al, 2009a). In this paper, 'linear' model, in which weights of influence factors are invariable, and 'non-linear' model, in which weights of influence factors are variable, are taken into account with some examples. Then, the 'non-linear' model is validated by using 100 tunnel collapse cases. It appears that 'non-linear' model allows us to have adapted weight values of influence factors to characteristics of given tunnel site. In order to make a better understanding and help for an effective use of the system, a series of operating processes of the system are built up. Then, by following the processes, the system is applied to a real-life tunnel project in very weak and varying ground conditions. Through this approach, it would be quite apparent that the tunnel collapse hazard indices are determined by well interlinked consideration of face mapping data as well as design/construction data. The calculated indices seem to be in good agreement with available electric resistivity distribution and design/construction status. In addition, This approach could enhance effective usage of face mapping data and lead timely and well corresponding field reactions to situation of weak tunnel faces.