• Title/Summary/Keyword: Small-sized Construction

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A Study on the Ground Vibration Reduction Characteristics of Air-Deck Blasting Method Using Paraffin Waxed Paper Tube (파라핀 지관 구조체를 활용한 Air-Deck 발파공법의 지반진동 저감특성에 관한 연구)

  • Gyeong-Jo, Min;Young-Keun, Kim;Chan-Hwi, Shin;Sang-Ho, Cho
    • Explosives and Blasting
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    • v.41 no.1
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    • pp.32-45
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    • 2023
  • Environmental regulations in Korea for blasting at industrial sites have conservative standards, which often result in reduced efficiency and cost-effectiveness due to the consideration of environmental regulations and public complaints. Therefore, there is a need for blasting methods that can reduce environmental damage while improving construction efficiency and cost-effectiveness. In this study, we analyzed the effects of the PA-Deck (Paraffin Air-Deck) blasting method, which is a kind of Air Decoupled Charge method in principle utilizing a paraffin-infused paper tube as an air gap, on reducing blasting hazards and improving blasting efficiency. The analysis also evaluated the effectiveness of newly applied equipment for collecting blasting vibration data, and derived the relationship between the explosion velocity and vibration velocity of explosives, and performed frequency analysis of the vertical component. The results of the blasting vibration velocity analysis showed that the Paraffin Waxed Paper Tube-based blasting method exhibited significantly lower vibration velocities compared to conventional blasting methods, and it was judged that more uniformly small-sized fragmented rocks were generated.

A Study about Successful Factors of e-Commerce on Chinese SMEs (중국 중소기업의 전자상거래 성공요인에 관한 연구)

  • Ge, Li;Chung, Chang-Kun;Sohn, Sung-Pyo
    • Korea Trade Review
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    • v.41 no.5
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    • pp.285-304
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    • 2016
  • e-Commerce in Small and Medium-sized Enterprises(SMEs) provides a platform for fair competition between SMEs and large enterprises, and brings economic benefits to SMEs. Thus in the recent years, the e-Commerce in SMEs developed rapidly. However, the overall proportion of e-Commerce in SMEs in China remains low, and many SMEs' decision-makers tend to feel that their business is relatively weak in terms of information construction of scale and financial management, thus they keep the 'wait and see' attitude about the e-Commerce development decisions. Therefore, SMEs are facing three puzzles about e-Commerce application. First, if the companies need to implement e-Commerce, what are the e-Commerce adoption decision factors. Second, what are the successful implementation factors of e-Commerce. And how about the relationship between them. The third is how to measure the implementation effect of e-Commerce. What is the performance evaluation factors of e-Commerce. In this paper, the theoretical and empirical exploration and research are conducted towards these SMEs. Considering the actual situation of SMEs, this paper builds a theoretical model, then puts forward relevant hypothesis. This paper analyzes present influencing factors based on enormous research papers, and finally discovers the critical successful factors in doing business with e-Commerce in SMEs by conducting Structural Equation Modeling. Five critical factors are verified by cases of enterprise by demonstration study. Lastly, we can draw a conclusion that the innovation ability of leaders, the IT support of leaders and e-Commerce strategies are the success factors of e-Commerce for Chinese SMEs.

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A Study on Exhaust Gas Characteristics of Heavy-duty Diesel Engines through Actual Vehicle Application of Non-influenced Temperature Condition Type Active Regeneration Method (온도조건 비영향형 복합재생방식 DPF의 실차적용을 통한 대형디젤기관의 배출가스 특성 연구)

  • Yun chul Lee;Sang ki Oh
    • Journal of ILASS-Korea
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    • v.29 no.2
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    • pp.53-59
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    • 2024
  • Cars are one of the main causes of air pollution in large cities, and 34.6% of domestic air pollution emissions come from mobile sources, of which cars account for 69.6%. In particular, the importance of nitrogen oxides (NOx) and particulate matter (PM), which are major pollutants in diesel vehicles, is increasing due to their high contribution to emissions. Therefore, in this study, the problem of natural regeneration caused by low exhaust gas temperature during low speed and low load operation was solved by applying a complex regeneration DPF that is not affected by temperature conditions to large diesel vehicles with higher driving time and engine displacement than small and medium-sized vehicles. And the feasibility of application to large diesel vehicles was reviewed by measuring the emission reduction efficiency. As a result of the reduction efficiency test on the actual vehicle durability product, PM showed a reduction efficiency of 84% to 86%, and the reduction efficiency of gaseous substances showed a high reduction efficiency of over 90%. The actual vehicle applicability test was completed with three driving patterns: village bus vehicle, police car, and road-going construction equipment vehicle, and no device problems occurred until the end of the test. Both load and no-load smoke measurement results showed a smoke reduction efficiency of over 96%.

Proposal of Connection Details for a Double Split Tee Connection Without a Shear tap (전단탭이 없는 상·하부 스플릿 티 접합부의 접합부상세 제안)

  • Yang, Jae Guen;Lee, Hyung Dong;Kim, Yong Boem;Pae, Da Sol
    • Journal of Korean Society of Steel Construction
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    • v.27 no.5
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    • pp.423-433
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    • 2015
  • A double split tee connection, which is a beam-column moment connection, shows different behavioral characteristics under the influences of the thickness of a T-stub flange, a high-strength bolt gauge distance, and the number and diameter of a high-strength bolt. A double split tee connection is idealized and designed that a flexural moment normally acting on connections can be resisted by a T-stub and a shear force by a shear tap. However, where a double split tee connection is adopted to a low-and medium-rise steel structure, a small-sized beam member can be adopted. Then, a shear tab may not be bolted to the web of a beam. This study was conducted to suggest the details of a connection to secure that a double split tee connection with a geometric shape has a sufficient capacity to resist a shear force. To verify this, this study was conducted to make a three-dimensional nonlinear finite element analysis on a double split tee connection.

An Analysis on the Educational Needs for the Smart Farm: Focusing on SMEs in Jeon-nam Area (중소·중견기업의 스마트팜 교육 수요 분석: 전남지역을 중심으로)

  • Hwang, Doo-hee;Park, Geum-Ju
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.1
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    • pp.649-655
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    • 2020
  • This study determined effective educational strategies by investigating and analyzing the related educational demands for SMEs (small and medium-sized enterprises) in the 4th Industrial Revolution based area of smart farms. In order to derive the approprate educational strategies, Importance-Performance Analysis (IPA) and Borich's Needs Assessment Model were conducted based on the smart farm technological field. As a result, the education demand survey showed high demand for production systems and intelligent farm machinery. In detail, Borich's analysis showed the need for pest prevention and diagnosis technology (8.03), network and analysis SW linkage technology (7.83), and intelligent farm worker-agricultural power system-electric energy hybrid technology (7.43). In contrast, smart plant factories (4.09), lighting technology for growth control (4.46) and structure construction technology (4.62) showed low demands. Based on this, the IPA portfolio shows that the network and analysis SW linkage technology and the CAN-based complex center are urgently needed. However, the technology that has already been developed, such as smart factory platform development, growth control lighting technology and structure construction technology, was oversized. Based on these results, it is possible to strategically suggest the customized training programs for industrial sectors of SMEs that reflect the needs for efficiently operating smart farms. This study also provides effective ways to operate the relevant training programs.

A Study on Technology Priorities for Green Highway (녹색도로 구현을 위한 기술 우선순위 결정에 관한 연구)

  • Lee, Yu-Hwa;Cho, Won-Bum;Kim, Se-Hwan
    • International Journal of Highway Engineering
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    • v.14 no.3
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    • pp.151-162
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    • 2012
  • It is not surprising to hear news about irresistible natural disasters all over the world due to climate change. Korean Government has focused on developing a variety of green technologies to reduce green house gasses, in particular, carbon dioxide. This study suggested 18 technology divisions for achieving green highway technology development in six different sub-sectors considering life-cycle of roadway and surveyed 29 highway and/or transportation professionals of three institutes using AHP(Analytical Hierarchy Process) analysis to construct "Green Highway"and realize carbon emission reductions and energy use efficiency in a road sector in Korea. Expert Choice Software was used to rank 18 technology divisions weighted by two-level choices. Transport Operating Infrastructure Improvement, Roadway Policy Implementation, Green Transportation(such as Pedestrian and Bicycle) were highly ranked by respondents according to results of the AHP modeling. Among the 18 divisions, technology policy for supporting R&D investments from development to commercialization was ranked as the most significant one to be focused. Green Transportation Facility Design/Construction/Operation and Eco-Friendly Roadway Plan were followed as expected since professionals have thought that the planning/design step of the life-cycle is a starting point to reduce carbon dioxide from roads more and more. Additionally, comparing the results with the Government investment trend 2006-2011 for the roads, it can be interpreted that the Government should invest to the R&D area more widely than before to promote element and core technology development for Green Highway Construction. Above all, small and mid-sized businesses have to be invested as well as encouraged to undertake green highwayrelated objects to accomplish the divisions which ranked high.

An Analysis of Determinants of Turnover Intent of Architectural Design Firms (건축 설계사무소 실무자의 이직의도 결정요인 분석)

  • Seo, Hee-Chang;Oh, Jung-Keun;Kim, Jea-Jun
    • Korean Journal of Construction Engineering and Management
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    • v.13 no.5
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    • pp.64-75
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    • 2012
  • Today organizations are making considerable efforts in order to maintain excellent talent, and in particular, they are focusing on understanding their intentions of changing jobs which are most highly correlated with job turnover. In the case of architectural design firms, its intensity of work is very high unlike industrial settings, and it not only takes much time to cultivate new men of talent and but also is characteristic that employees can change livery easily because of the flexible labor market. The turnover rated by National Statistical Office indicates that specialized, scientific and technical service industry including the architectural design firm has a relatively high turnover rate compared to the average of the turnover rate of the overall industries. However, studies on intentions of changing jobs until now were conducted focused on employees engaged in other industrial areas, and it is true that studies regarding intentions of changing jobs of practitioners of architectural design firms are very insufficient. In this context, the present study aimed to draw determinants affecting intentions of changing jobs of practitioners of architectural design firms, to objectively understand the practitioners' intentions of changing jobs through importance analysis by each factor based on this and to make a comparative analysis of differences between the large scale architectural design firms and the small and medium sized architectural design firms.

A Study on Flood Discharge Capacity and Hydraulic Characteristic of Labyrinth Weir as a Side-Channel Spillway (래버린스 웨어를 적용한 측수로형 여수로의 홍수배제능력 및 수리학적 특성 연구)

  • Park, Sae-Hoon;Moon, Young-Il
    • Journal of Korea Water Resources Association
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    • v.41 no.1
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    • pp.65-74
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    • 2008
  • The small and medium sized dams have the fill dam type of a lot of occasions, which are often weak in cases of major floods. For this reason, although a countermeasure is in great need, due to the importance of the facilities and financial situations, no direct safety measures have been taken. In this study, in order to minimize construction expenditure for practical safety measures in cases of major floods, the overflow section of spillway has been analyzed focusing on how the overflow capacity will increase in the case of partially rebuilding a part of the overflow section of spillway favorable for hydraulic conditions. The Labyrinth weir and movable weir was chosen for reconstruction models of the overflow section. Moreover, for analyzing the after-effects of the reconstruction, a small scale dam was temporarily chosen for various experiments such as the hydraulic model testing and the three dimension numerical evaluation through the use of Flow-3D.

A Study on Thermal Performance Comparison between Large and Small Sized Plate Heat Exchanger (판형 열교환기 크기에 따른 전열성능 비교에 관한 연구)

  • Park, Jae-Hong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.2
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    • pp.528-534
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    • 2020
  • The early development and use of plate heat exchangers (PHE) were in response to stringent statutory requirements from dairy products in the late 19th century, but PHEs were not exploited commercially until the 1920s. Since then, although the basic concept of PHEs has changed little, its design and construction have progressed significantly to accommodate higher temperatures and pressures, as well as large heat exchanging capacities. The development of current chevron-type corrugated heat plates has been ongoing since the oil shock in the 1970s to improve energy efficiency. The development trend of PHEs is consistent with the development of larger heat plates with better thermal efficiency, lower pressure drop, and good flow distribution. In this study, the thermal performance of small heat plates (PHE-S) and large heat plates (PHE-L) with the same plate depth and corrugation pitch were analyzed experimentally for each channel (H, M, and L type) to suggest development directions of heat plates. The test results showed that for the convectional heat transfer coefficient, the PHE-S was on average, 16.5% higher in the H type, 25% higher in the M type, and 40% higher in the L type than PHE-L. In the case of the pressure drop, the PHE-S was 19% higher in the H type, 46% higher in the M type, and 61% higher in the L type than PHE-L. These results were attributed to the differences in fluid distribution areas between the PHE-S and PHE-L, among other potential causes.

A Study on the Global Market Success through the Customer Value-based Corporate Strategy : The Case of Hilti (고객가치 기반 기업전략을 통한 글로벌 시장성공 : 전동공구기업 힐티의 사례)

  • Hong, Song Hon
    • International Commerce and Information Review
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    • v.16 no.5
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    • pp.151-178
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    • 2014
  • The objective of the present case study is to analysis how effectively Hilti, which is a former family firm owned and managed by a family in Liechtenstein as a tiny european country, a land sandwiched between Switzerland and Austria, has made a global market success. Liechtenstein has $160km^2$ land and about 36,000 residents. Despite its small size of country, however, Hilti Corporation doesn't view its location as a liability in its business strategy. Hilti is a global leading provider of professional power tools in building, mining, civil engineering etc. Also, Hilti is a firm with a clear vision to become the leading industry partner for construction professionals and building installations through customer focus, high quality equipment, and tools and systems specially designed for specific jobs. This study considered Hilti as a good case, which verifies that born-conditions, endogenous factors according to Michael Porters diamond model does not decisive role more for international competitiveness of firms. Lessons from Hilti are that in order to obtain and sustain the global competitiveness of small and medium-sized firms in Korean manufacturing sector under high production cost, they have to do actively innovative. Also they can give to customers newer and higher customer-values than competitors in abroad give. The case summarizes that the strategy of Hilti for the global market success is comprised of several factors: Technological and organizational innovation, and a clear customer-value oriented business strategy and its implementation. Innovation and its integration into marketing for the customers value creation is central to Hilti's Success. The present case study is expected to provide insights and implication for many firms in Korea that are seeking to secure global presence and market success.

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