• Title/Summary/Keyword: new boundary condition

Search Result 324, Processing Time 0.028 seconds

When Does Human Capital Facilitate the Corporate Innovation Performance?: The Moderating Effect of International Experience (인적자본은 언제 기업의 혁신성과를 향상시킬 수 있는가?: 국제화 경험의 조절효과를 중심으로)

  • Gwon, Sun-Hwan;Kwon, Jong-Wook;Shin, Mann-Soo
    • Asia-Pacific Journal of Business
    • /
    • v.11 no.3
    • /
    • pp.47-61
    • /
    • 2020
  • Purpose - This study investigates the relationship between firm-specific, general human capital and corporate innovation performance. Also, we examine when this relationship is more salient. Design/methodology/approach - We collected 1,195 survey data related to a sample of corporate innovation performance and human capital from 1) Korea Research for Vocational Education and Training and 2) NICE information service in Korea. In order to examine the corporate innovation performance, we use the ordered logit model. Findings - First, we find robust supports for our hypothesis that firm-specific and general human capital increase corporate innovation performance. Second, the effect of general human capital on corporate innovation performance is stronger when this relationship is combined with the firm international experience. Research implications or Originality - By integrating the human capital theory and corporate innovation literature, we propose that firm-specific and general human capital are the important determinant of innovation performance. The firm-specific human capital may increase innovation efficiencies. Also, retaining higher-quality general human capital is considered as an important innovation strategy since firms with higher-quality general human capital make greater innovation performance. Further, we show that the firm international experience is the crucial boundary condition. As a firm's experience in internationalization increases, firms can enhance the opportunities to develop new products by combining the skills and knowledge derived from general human capital with the experience gained through internationalization.

Buckling treatment of piezoelectric functionally graded graphene platelets micro plates

  • Abbaspour, Fatemeh;Arvin, Hadi
    • Steel and Composite Structures
    • /
    • v.38 no.3
    • /
    • pp.337-353
    • /
    • 2021
  • Micro-electro-mechanical systems (MEMS) are widely employed in sensors, biomedical devices, optic sectors, and micro-accelerometers. New reinforcement materials such as carbon nanotubes as well as graphene platelets provide stiffer structures with controllable mechanical specifications by changing the graphene platelet features. This paper deals with buckling analyses of functionally graded graphene platelets micro plates with two piezoelectric layers subjected to external applied voltage. Governing equations are based on Kirchhoff plate theory assumptions beside the modified couple stress theory to incorporate the micro scale influences. A uniform temperature change and external electric field are regarded along the micro plate thickness. Moreover, an external in-plane mechanical load is uniformly distributed along the micro plate edges. The Hamilton's principle is employed to extract the governing equations. The material properties of each composite layer reinforced with graphene platelets of the considered micro plate are evaluated by the Halpin-Tsai micromechanical model. The governing equations are solved by the Navier's approach for the case of simply-supported boundary condition. The effects of the external applied voltage, the material length scale parameter, the thickness of the piezoelectric layers, the side, the length and the weight fraction of the graphene platelets as well as the graphene platelets distribution pattern on the critical buckling temperature change and on the critical buckling in-plane load are investigated. The outcomes illustrate the reduction of the thermal buckling strength independent of the graphene platelets distribution pattern while meanwhile the mechanical buckling strength is promoted. Furthermore, a negative voltage, -50 Volt, strengthens the micro plate stability against the thermal buckling occurrence about 9% while a positive voltage, 50 Volt, decreases the critical buckling load about 9% independent of the graphene platelet distribution pattern.

Dynamic vulnerability assessment and damage prediction of RC columns subjected to severe impulsive loading

  • Abedini, Masoud;Zhang, Chunwei
    • Structural Engineering and Mechanics
    • /
    • v.77 no.4
    • /
    • pp.441-461
    • /
    • 2021
  • Reinforced concrete (RC) columns are crucial in building structures and they are of higher vulnerability to terrorist threat than any other structural elements. Thus it is of great interest and necessity to achieve a comprehensive understanding of the possible responses of RC columns when exposed to high intensive blast loads. The primary objective of this study is to derive analytical formulas to assess vulnerability of RC columns using an advanced numerical modelling approach. This investigation is necessary as the effect of blast loads would be minimal to the RC structure if the explosive charge is located at the safe standoff distance from the main columns in the building and therefore minimizes the chance of disastrous collapse of the RC columns. In the current research, finite element model is developed for RC columns using LS-DYNA program that includes a comprehensive discussion of the material models, element formulation, boundary condition and loading methods. Numerical model is validated to aid in the study of RC column testing against the explosion field test results. Residual capacity of RC column is selected as damage criteria. Intensive investigations using Arbitrary Lagrangian Eulerian (ALE) methodology are then implemented to evaluate the influence of scaled distance, column dimension, concrete and steel reinforcement properties and axial load index on the vulnerability of RC columns. The generated empirical formulae can be used by the designers to predict a damage degree of new column design when consider explosive loads. With an extensive knowledge on the vulnerability assessment of RC structures under blast explosion, advancement to the convention design of structural elements can be achieved to improve the column survivability, while reducing the lethality of explosive attack and in turn providing a safer environment for the public.

Optimum arrangement of stiffener on the buckling behaviour of stiffened composite panels with reinforced elliptical cutouts subjected to non-uniform edge load

  • Kalgutkar, Akshay Prakash;Banerjee, Sauvik;Rajanna, T.
    • Steel and Composite Structures
    • /
    • v.42 no.4
    • /
    • pp.427-446
    • /
    • 2022
  • Cutouts in the beams or plates are often unavoidable due to inspection, maintenance, ventilation, structural aesthetics purpose, and sometimes to lighten the structures. Therefore, there will be a substantial reduction in the strength of the structure due to the introduction of the cutouts. However, these cutouts can be reinforced with the different patterns of ribs (stiffener) to enhance the strength of the structure. The present study highlights the influence of the elliptical cutout reinforced with a different pattern of ribs on the stability performance of such stiffened composite panels subjected to non-uniform edge loads by employing the Finite element (FE) technique. In the present formulation, a 9-noded heterosis element is used to model the skin, and a 3-noded isoparametric beam element is used to simulate the rib that is attached around a cutout in different patterns. The displacement compatibility condition is employed between the plate and stiffener, and arbitrary orientations are taken care by introducing respective transformation matrices. The effect of shear deformation and rotary inertia are incorporated in the formulation. A new mesh configuration is developed to house the attached ribs around an elliptical cutout with different patterns. Initially, a study is performed on the panels with different stiffener schemes for various ply orientations and for different stiffener depth to width ratios (ds/bs) to determine an optimal stiffener configuration. Further, various parametric studies are conducted on an obtained optimal stiffened panel to understand the effect of cutout size, cutout orientation, panel aspect ratio, and boundary conditions. Finally, from the analysis, it can be observed that the arrangement of the stiffener attached to a panel has a major impact on the buckling capacity of the stiffened panel. The stiffener's depth to width ratio also significantly influences the buckling characteristic.

New Method of Computing the Stokes Drift Including Shear Effect in the Cross-Sectional Flow Field (유수단면 흐름장에서 Shear 효과를 갖는 Stokes Drift의 계산법)

  • Kim, Jong-Hwa;Park, Byong-Su
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.33 no.1
    • /
    • pp.9-26
    • /
    • 1997
  • Stokes drift(SD) and Lagrangian discharge(LD) are important factors for analysis of flushing time, tidal exchange, solute transport and pollutant dispersion. The factors should be calculated using the approached method to flow phenomena. The aim of this paper re-examines the previous procedures for computing the SD and LD, and is to propose the new method approached to stratified flow field in the cross-section of coastal region, e.g. Masan Bay. The intensity of velocity near the bottom boundary layer(BBL) depends on the sea-bed irregularity in the coastal estuaries. So we calculated the depth mean velocity(DMV) considering that of BBL omitted in Kjerfve's calculation method. It revealed that BBL effect resulting in application of the bay acts largely on DMV in half more among 1l stations. The new expression of SD and LD per unit width in the cross-section using the developed DMV and proposed decomposition procedure of current were derived as follow : $$Q=u_0+\frac{1}{2}H_1{U_1cos(\varphi_h-\varphi_u)+U_3cos(\varphi_h-\varphi{ud})} LD ED SD$(Q_{skim}+Q_{sk2}) The third term, $Q_{sk2}$, on the right-hand of the equation is showed newly and arise from vertical oscillatory shear. According to the results applied in 3 cross-sections including 11 stations of the bay, the volume difference between proposed and previous SD was founded to be almost 2 times more at some stations. But their mean transport volumes over all stations are 18% less than the previous SD. Among two terms of SD, the flux of second term, $Q_{skim}$, is larger than third term, $Q_{sk2}$, in the main channel of cross-section, so that $Q_{skim}$ has a strong dependence on the tidal pumping, whereas third term is larger than second in the marginal channel. It means that $Q_{sk2}$ has trapping or shear effect more than tidal pumping phenomena. Maximum range of the fluctuation in LD is 40% as compared with the previous equations, but mean range of it is showed 11% at all stations, namely, small change. It mean that two components of SD interact as compensating flow. Therefore, the computation of SD and LD depend on decomposition procedure of velocity component in obtaining the volume transport of temporal and spacial flow through channels. The calculation of SD and LD proposed here can separate the shear effect from the previous SD component, so can be applied to non-uniform flow condition of cross-section, namely, baroclinic flow field.

  • PDF

New Platform of Orientalism-Based Design Education (동양성 기반의 디자인 교육의 새로운 플랫폼)

  • Choi, Kyung Ran
    • Korea Science and Art Forum
    • /
    • v.20
    • /
    • pp.455-464
    • /
    • 2015
  • As the recognition toward the Korean design education development to nurture creative talents for the future society has been expanded recently, various supports and promoting strategies are being suggested. This study suggests the orientalism-based new design education platform in design education field to nurture creative talents. To have the competitiveness of creative talent nurturing, the system and education programs to rear creative talents are required. The purpose of this study is to suggest the new platform for the change of direction in design education and search for the methods in detail. The research process can be described as following: First, this study stated about the research background and its boundary. Based on the literature review and the condition of the crisis of Korean design education (Korean Industrial Statistic Investigation), it described the current condition and the characteristics. Second, this study stated about the education which will be disappeared in the information society, the change of direction in design education, and the new platform. In the current study, the change toward the strategies that give priority to the growth strategies on the knowledge-based industry was stated. Third, this study stated about that the future design education should be centered on the orientalism-based creativity in the trend changing to the six conditions for the future talents and the beliefs and values toward Asia, and what methods should be sought to achieve this trend. It suggested focusing on the aim for the direction for College education and its program curriculums as the solutions in detail. Fourth, based on the contents stated earlier in this study, it stated synthetically the direction of practice through the network of the design cluster and derived the implications. In conclusion, based on the recent orientalism-based mind, this study suggested the ways to find the identity of Korean design education itself and have the competitiveness in design education programs. The ways to secure them is to come from the integrated system innovation of the network. By actively applying the design clusters, colleges and universities, designers, studios, government policy organizations, design institutes, corporates, media, and fairs, this study suggests the sustainable education system and the practical methods.

The Moderating Role of the Relationship between Product and Reward in the Medium Effect (상품과 보상물의 관련성이 매개물 효과에 미치는 영향)

  • Hur, Chung;Kim, Hui-Yeong;Ha, Young-Won;YOON, HYUNG GI
    • (The) Korean Journal of Advertising
    • /
    • v.28 no.6
    • /
    • pp.35-54
    • /
    • 2017
  • The importance of utilizing an effective reward program has been emphasized as a tool for promotional strategies to acquire and retain customers. When consumers participate in a reward frequency program, they tend to focus more on points or mileage than the actual reward itself. This phenomenon is what Hsee, Yu, Zhang, and Zhang (2003) called "medium maximization." In this article, we hypopthesize that the medium effect may disappear when there is a close relationship between the product and the reward as it evokes the correlation of the two directly. The results of the current research show that the medium effect disappears in a strong relation condition while it does exist in a weak relation condition. Furthermore, we found that these results cannot be explained under an alternative "evaluability hypothesis" as Hsee, Loewenstein, Blount, and Bazerman (1999) and Hsee (1996) claimed. Even when we provided price range information as well as medium information, the medium effect still occurred. In this article, we explored boundary conditions for the medium effect and demonstrated the moderating effect of the relationship between products and rewards. Practical implications of the findings were also discussed for designing separate reward programs.

The Production-And-Marketing System and the Regional Division in a Traditional Industrial District: Hemp Fabric Handicrafts in Andong (안동 삼베 수공업산지의 생산유통체제와 지역분화)

  • Lee, Chul-Woo
    • Journal of the Korean association of regional geographers
    • /
    • v.3 no.1
    • /
    • pp.135-154
    • /
    • 1997
  • The purpose of this study is to clarify the reason of the change of production-and-marketing system and of the regional division. The data for this study were collected by administering interviews with people engaging in hemp fabric industry: namely, craftsmen and managers in the production and marketing of "hemp fabric" handcraft. The summary of this study is as follows: First, the hemp fabric industry is a main subsidiary business of agriculture in Andong. The process of making hemp fabric heavily depends on manual labor. The process is divided into five stages: namely, cultivating hemp, pre-reeling, reeling, weaving, and colouring. Second, Andong "hemp fabric" handicrafts industry had been continuously growth until the late 1960s. During the period of Japan colonization, it was under boom condition: while the other traditional fabric industries were declined. In the 1970s, the decrease of the demand of hemp fabric was the result of mass production of substitute goods on factory system: while, in the 1980s, the growth of per capital income play an important role in bringing about the increased demand of hemp fabric. Third, in the 1980s. production-and-marketing system was changed as the result of the effort to improve the quality and the process, the advanced age of craftsmen, and the weak function of existing marketing systems. The social division of labor within the district is well developed between cultivating hemp, reeling and weaving. The social division of labor is also found in the partly process of handcratfs, and between the production and marketing. The social division of labor between production and marketing is not strongly developed to establish a reliable enterprise that develops a new product and opens a new market. Fourth, the spatial boundary of the production of hemp fabric handcrafts becomes limited into a special region based on the regional specialization of hemp cultivating and the differentiation of utilization of labor.

  • PDF

60 Years since the Armistice Treaty, the NLL and the North-Western Islands (정전협정 60년, NLL과 서북 도서)

  • Jhe, Seong-Ho
    • Strategy21
    • /
    • s.31
    • /
    • pp.27-56
    • /
    • 2013
  • The United Nations Command (UNC) and the communist North failed to reach an agreement on where the maritime demarcation line should be drawn in the process of signing a truce after the Korean War because of the starkly different positions on the boundary of their territorial waters. As a result, the Armistice Treaty was signed on July 1953 without clarification about the maritime border. In the following month, Commander of the UNC unilaterally declared the Northern Limit Line (NLL) as a complementing measure to the Armistice. Referring to this, North Korea and its followers in South Korea wrongfully argue that the NLL is a "ghost line" that was established not based on the international law. However, one should note that the waters south of the NLL has always been under South Korea's jurisdiction since Korea's independence from Japan on August 15, 1945. There is no need to ask North Korea's approval for declaring the territorial waters that had already been under our sovereign jurisdiction. We do not need North Korea's approval just as we do not need Japan's approval with regard to our sovereign right over Dokdo. The legal status of the NLL may be explained with the following three characteristics. First, the NLL is a de facto maritime borderline that defines the territorial waters under the respective jurisdiction of the two divided countries. Second, the NLL in the West Sea also serves as a de facto military demarcation line at sea that can be likened to the border on the ground. Third, as a contacting line where the sea areas controlled by the two Koreas meet, the NLL is a maritime non-aggression line that was established on the legal basis of the 'acquiescence' element stipulated by the Inter-Korea Basic Agreement (article 11) and the Supplement on the Non-aggression principle (article 10). Particularly from the perspective of the domestic law, the NLL should be understood as a boundary defining areas controlled by temporarily divided states (not two different states) because the problem exists between a legitimate central government (South Korea) and an anti-government group (North Korea). In this sense, the NLL problem should be viewed not in terms of territorial preservation or expansion. Rather, it should be understood as a matter of national identity related to territorial sovereignty and national pride. North Korea's continuous efforts to problematize the NLL may be part of its strategy to nullify the Armistice Treaty. In other words, North Korea tries to take away the basis of the NLL by abrogating the Armistice Treaty and creating a condition in which the United Nations Command can be dissolved. By doing so, North Korea may be able to start the process for the peace treaty with the United States and reestablish a maritime line of its interest. So, North Korea's rationale behind making the NLL a disputed line is to deny the effectiveness of the NLL and ask for the establishment of a new legal boundary. Such an effort should be understood as part of a strategy to make the NLL question a political and military dispute (the similar motivation can be found in Japan's effort to make Dokdo a disputed Island). Therefore, the South Korean government should not accommodate such hidden intentions and strategy of North Korea. The NLL has been the de facto maritime border (that defines our territorial waters) and military demarcation line at sea that we have defended with a lot of sacrifice for the last sixty years. This is the line that our government and the military must defend in the future as we have done so far. Our commitment to the defense of the NLL is not only a matter of national policy protecting territorial sovereignty and jurisdiction; it is also our responsibility for those who were fallen while defending the North-Western Islands and the NLL.

  • PDF

The Study on New Radiating Structure with Multi-Layered Two-Dimensional Metallic Disk Array for Shaping flat-Topped Element Pattern (구형 빔 패턴 형성을 위한 다층 이차원 원형 도체 배열을 갖는 새로운 방사 구조에 대한 연구)

  • 엄순영;스코벨레프;전순익;최재익;박한규
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.13 no.7
    • /
    • pp.667-678
    • /
    • 2002
  • In this paper, a new radiating structure with a multi-layered two-dimensional metallic disk array was proposed for shaping the flat-topped element pattern. It is an infinite periodic planar array structure with metallic disks finitely stacked above the radiating circular waveguide apertures. The theoretical analysis was in detail performed using rigid full-wave analysis, and was based on modal representations for the fields in the partial regions of the array structure and for the currents on the metallic disks. The final system of linear algebraic equations was derived using the orthogonal property of vector wave functions, mode-matching method, boundary conditions and Galerkin's method, and also their unknown modal coefficients needed for calculation of the array characteristics were determined by Gauss elimination method. The application of the algorithm was demonstrated in an array design for shaping the flat-topped element patterns of $\pm$20$^{\circ}$ beam width in Ka-band. The optimal design parameters normalized by a wavelength for general applications are presented, which are obtained through optimization process on the basis of simulation and design experience. A Ka-band experimental breadboard with symmetric nineteen elements was fabricated to compare simulation results with experimental results. The metallic disks array structure stacked above the radiating circular waveguide apertures was realized using ion-beam deposition method on thin polymer films. It was shown that the calculated and measured element patterns of the breadboard were in very close agreement within the beam scanning range. The result analysis for side lobe and grating lobe was done, and also a blindness phenomenon was discussed, which may cause by multi-layered metallic disk structure at the broadside. Input VSWR of the breadboard was less than 1.14, and its gains measured at 29.0 GHz. 29.5 GHz and 30 GHz were 10.2 dB, 10.0 dB and 10.7 dB, respectively. The experimental and simulation results showed that the proposed multi-layered metallic disk array structure could shape the efficient flat-topped element pattern.