346 research outputs found

    Spatial stochastic programming model for timber and core area management under risk of stand-replacing fire, A

    Get PDF
    2012 Fall.Includes bibliographical references.Forest harvest scheduling has been modeled using deterministic and stochastic programming models. Past models seldom address explicit spatial forest management concerns under the influence of natural disturbances. In this research study, we employ multistage full recourse stochastic programming models to explore the challenges and advantages of building spatial optimization models that account for the influences of random stand-replacing fires. Our exploratory test models simultaneously consider timber harvest and mature forest core area objectives. Each model run reports first-period harvesting decisions for each stand based on a sample set of random fire. We integrate multiple model runs to evaluate the persistence of period-one solutions under the influence of stochastic fires. Follow-up simulations were used to support multiple comparisons of different candidate forest management alternatives for the first time period. Test case results indicate that integrating the occurrence of stand-replacing fire into forest harvest scheduling models could improve the quality of long-term spatially explicit forest plans

    A secure image steganography based on JND model

    Get PDF
    Minimizing distortion produced by embedding process is very important to improve the security of hidden message and maintain the high visual quality of stego images. To achieve these objectives, an effective strategy is to perform pixel selection which is well-known as a channel selection rule. In this approach, a pixel associated with the smallest image degradation is chosen to carry secret bits. From these facts, in this paper, a new secure channel selection rule for digital images in spatial domain is designed and proposed. In this new approach, the modified matrix embedding method is utilized as data hiding method because it introduces more than one embedding change to be performed. This enables us to select a suitable pixel to embed message bits with less degradation yielded in a stego-image. In pixel selection of the proposed method, a just noticeable difference value and gradient value of a considering pixel are employed together. The experimental results (which were conducted on 10,000 uncompressed images) indicate that stego images of the proposed approach achieve a higher perceptual quality and security than those of the stego-images created by the previous approaches

    The Organizational Culture Strategy SMEs During Economic Crises

    Get PDF
    The importance of organizational culture in the operation and performance of businesses has been widely acknowledged, but there is inconsistency in findings about the impact of culture on organizational performance across studies. This study aimed to achieve two objectives: first, to establish the relationship between the quality of accounting information systems (AIS), organizational culture, and the financial performance of small and medium enterprises (SMEs) in Vietnam; and second, to survey the organizational culture strategy of Vietnamese SMEs in the context of economic crises. The study survey was conducted in May 2023 and involved 242 SMEs in Vietnam. The research model was tested using Smart PLS. The results suggest that AIS has a positive relationship with both organizational culture and the financial performance of SMEs. However, organizational culture only affects financial performance related to organizational adaptability during a crisis. Moreover, a flexible, external adaptation, and balanced cultural approach strategy has a significant impact on the financial performance of SMEs. During a crisis, managers expect employees to adapt in order to achieve strategic goals and plans while simultaneously balancing stability, engagement, and employee satisfaction to achieve organizational effectiveness. Doi: 10.28991/ESJ-2023-07-06-015 Full Text: PD

    Vietnam. La arquitectura religiosa contemporánea como un bien escaso

    Get PDF
    [Abstract] In the 16th century, the first Spanish and Portuguese Dominican missionaries arrived in Southeast Asia, included Vietnam, but only after the first decades of the seventeenth century, Christianity began to take hold and lived through different episodes of the Proclamation of the Christian faith: first it was tolerated and then abandoned by the dynasties, supported by the colonialists, declined in the north by the communists, it expanded in the south under the Republic of Vietnam and stabilized until now after the reunification of the country followed by a long breakage due to political change. Along with this story, sacred architecture was interpreted in various ways to define identities in religious life and faith. However, the most difficult period of religious architecture is not only in the political conflict of the past, but also until now, the time of the economic boom. The change of values as well as the aesthetic system make sacred art and architecture remain a giant wheel stuck in mud.[Resumen] En el siglo XVI, los primeros misioneros dominicos españoles y portugueses llegaron al sudeste asiático, incluso a Vietnam, pero solo después de las primeras décadas del siglo XVII, el cristianismo comenzó a afianzarse y vivió diferentes episodios de la Proclamación de la fe cristiana: primero fue tolerado y luego abandonado por las dinastías, apoyado por los colonialistas, declinado en el al norte por los comunistas, se expandió en el sur bajo la República de Vietnam y se estabilizó hasta ahora después de la reunificación del país seguida de una larga ruptura debido al cambio político. Junto con esta historia, la arquitectura sagrada se interpretó de diversas formas para definir identidades en la vida religiosa y en la fe. Sin embargo, el período más difícil de la arquitectura religiosa no es solo en el conflicto político del pasado, sino también hasta ahora, la época del boom económico. El cambio de valores así como el sistema estético hacen que el arte y la arquitectura sagrados sigan siendo una rueda gigante atascada en el barro

    Dynamic Texture Map Based Artifact Reduction For Compressed Videos

    Get PDF
    This paper proposes a method of artifact reduction in compressed videos using dynamic texture map together with artifact maps and 3D - fuzzy filters. To preserve better details during filtering process, the authors introduce a novel method to construct a texture map for video sequences called dynamic texture map. Then, temporal arifacts such as flicker artifacts and mosquito artifacts are also estimated by advanced flicker maps and mosquito maps. These maps combined with fuzzy filters are applied to intraframe and interframe pixels to enhancecompressed videos. Simulation results verify the advanced performance of the proposed fuzzy filtering scheme in term of visual quality, SSIM, PSNR and flicker metrics in comparisionwith existing state of the art methods

    Effect of Creep and Shrinkage model in calculation of long-term deflection of three-span solid slab continuous prestressed concrete bridge

    Get PDF
    Shrinkage and creep effect significantly to the long-term deflection of prestressed concrete bridge. The proper shrinkage and creep models should be developed to meet the requirements of deflection effect calculation. There are many models has been researched and developed. Each specification, such as ASSHTO, Eurocode, ACI and CEB-FIB, has their own model of shrinkage and creep by considering different input parameter. The long-term deflection calculation is also different in each specification as a result. In this paper, several shrinkage and creep models were selected and reviewed to see the difference and compare by using popular concrete grade in Vietnamese bridge building     (C40 and C45, equivalent to 40 and 45 Mpa, respectively). Those selected shrinkage and creep models are applied in calculation of deflection for a typical three-span continuous solid slab prestressed concrete bridge. The calculation result show the significant different of long-term deflection and the ASSHTO shrinkage and creep model show the biggest deflection
    corecore