A first order system model is proposed for simulating the influence of stress stimulation on fracture strength during fracture healing. To validate the model, the diaphyses of bilateral tibiae in 70 New Zealand rabbit...A first order system model is proposed for simulating the influence of stress stimulation on fracture strength during fracture healing. To validate the model, the diaphyses of bilateral tibiae in 70 New Zealand rabbits were osteotomized and fixed with rigid plates and stress-relaxation plates, respectively. Stress shielding rate and ultimate bending strength of the healing bone were measured at 2 to 48 weeks postoperatively. Ratios of stress stimulation and fracture strength of the healing bone to those of intact bone were taken as the system input and output. The assumed first order system model can approximate the experimental data on fracture strength from the input of stress stimulation over time, both for the rigid plate group and the stress-relaxation plate group, with different system parameters of time constant and gain. The fitting curve indicates that the effect of mechanical stimulus occurs mainly in late stages of healing. First order system can model the stress adaptation process of fracture healing. This approach presents a simple bio-mathematical model of the relationship between stress stimulation and fracture strength, and has the potential to optimize planning of functional exercises and conduct parametric studies.展开更多
Approaches to building renovation require high professional levels, interdisciplinary elements, team work and time to study and do research on the buildings. The process of renovating historic buildings is made up of ...Approaches to building renovation require high professional levels, interdisciplinary elements, team work and time to study and do research on the buildings. The process of renovating historic buildings is made up of agreements and compromises between the interests of the government, common interests, and the motives and interests of individual owners and prospective investors. Research that deals with any portion of cultural heritages always carried out very precisely, but there is still no precise knowledge of how to define a system and draw up a model that accurately represents a cultural heritage. In the existing literature on this topic, the authors have written about the different views of how to explain the construction project as a system. While many authors focus on ＂sub-phases＂ directly connected to the building of an object, the process involved in the construction phase often neglects the phases required before beginning work, which culminates in a logical sequence in the process of preparing a project. Irregularities or deficiencies which occur during the preparation process of a project often directly impact the construction itself. What the scope of this impact depends on the approach of the contractual organization, the organization of construction companies and on co-operation between the customer （or architects） and the contractors. Unlike the projects for newly built objects, the conservation projects of cultural heritage are not only more demanding because of lack of knowledge of the building materials, construction, foundation and interaction of the mentioned individual parts into a unit called a building. The authors analyzed the structural aspects of building conservation which were suggested by Beckmaun and Bowles and another methodology, which was developed as part of the 5th framework program for the purpose of providing a comprehensive and interdisciplinary treatment of the revitalization of a historical city. The authors found that both methodologies do not include modern IT tools and methods. By analyzing and monitoring the restoration of historic buildings in Slovenia, specifically in the city of Maribor （including all documentation, interviews and direct views） the authors found that the project was regarded as a collection of individual projects rather than a unified whole （a system）. The authors have demonstrated the consequences of structuring a historic building restoration project in a non-systemic way. This type of project can be classified as a non-sustainable renovation. In this article, at first the authors will try to clarify what types of systems and subsystems are considered in renovating historic buildings. The authors show when and why a system becomes stochastic （a probability） and in the end what would be needed to successfully re-establish it back to a determined system. By analyzing the work and reconstruction of old buildings in Maribor, the authors found that it would be necessary to give a new framework with IT tools for the preparation of a historic building restoration project.展开更多
基金Project (No. 39470698) supported by the National Natural Science Foundation of China
文摘A first order system model is proposed for simulating the influence of stress stimulation on fracture strength during fracture healing. To validate the model, the diaphyses of bilateral tibiae in 70 New Zealand rabbits were osteotomized and fixed with rigid plates and stress-relaxation plates, respectively. Stress shielding rate and ultimate bending strength of the healing bone were measured at 2 to 48 weeks postoperatively. Ratios of stress stimulation and fracture strength of the healing bone to those of intact bone were taken as the system input and output. The assumed first order system model can approximate the experimental data on fracture strength from the input of stress stimulation over time, both for the rigid plate group and the stress-relaxation plate group, with different system parameters of time constant and gain. The fitting curve indicates that the effect of mechanical stimulus occurs mainly in late stages of healing. First order system can model the stress adaptation process of fracture healing. This approach presents a simple bio-mathematical model of the relationship between stress stimulation and fracture strength, and has the potential to optimize planning of functional exercises and conduct parametric studies.
文摘Approaches to building renovation require high professional levels, interdisciplinary elements, team work and time to study and do research on the buildings. The process of renovating historic buildings is made up of agreements and compromises between the interests of the government, common interests, and the motives and interests of individual owners and prospective investors. Research that deals with any portion of cultural heritages always carried out very precisely, but there is still no precise knowledge of how to define a system and draw up a model that accurately represents a cultural heritage. In the existing literature on this topic, the authors have written about the different views of how to explain the construction project as a system. While many authors focus on ＂sub-phases＂ directly connected to the building of an object, the process involved in the construction phase often neglects the phases required before beginning work, which culminates in a logical sequence in the process of preparing a project. Irregularities or deficiencies which occur during the preparation process of a project often directly impact the construction itself. What the scope of this impact depends on the approach of the contractual organization, the organization of construction companies and on co-operation between the customer （or architects） and the contractors. Unlike the projects for newly built objects, the conservation projects of cultural heritage are not only more demanding because of lack of knowledge of the building materials, construction, foundation and interaction of the mentioned individual parts into a unit called a building. The authors analyzed the structural aspects of building conservation which were suggested by Beckmaun and Bowles and another methodology, which was developed as part of the 5th framework program for the purpose of providing a comprehensive and interdisciplinary treatment of the revitalization of a historical city. The authors found that both methodologies do not include modern IT tools and methods. By analyzing and monitoring the restoration of historic buildings in Slovenia, specifically in the city of Maribor （including all documentation, interviews and direct views） the authors found that the project was regarded as a collection of individual projects rather than a unified whole （a system）. The authors have demonstrated the consequences of structuring a historic building restoration project in a non-systemic way. This type of project can be classified as a non-sustainable renovation. In this article, at first the authors will try to clarify what types of systems and subsystems are considered in renovating historic buildings. The authors show when and why a system becomes stochastic （a probability） and in the end what would be needed to successfully re-establish it back to a determined system. By analyzing the work and reconstruction of old buildings in Maribor, the authors found that it would be necessary to give a new framework with IT tools for the preparation of a historic building restoration project.
