جستجوی مقالات مرتبط با کلیدواژه « تحلیل شبکه » در نشریات گروه « علوم پایه »

In today's competitive environment, without investing in building strong and secure relationships between employees, they cannot be expected to perform tasks efficiently. Organizational network analysis is one of the applications of social network analysis method. Therefore, the purpose of this research is to analyze and map the internal and external communication networks of the Forests and Rangelands Research Institute. The statistical population in this study consists of managers and faculty members of the Forests and Rangelands Research Institute of the country who answered the research questions through the counting method. According to the results obtained in the research, in the field of intra-organizational communication, the most communications are related to Soil Conservation and Watershed Management Research Institute, Soil and Water Research Institute, National Animal Science Research Institute, Seed and Seedling Registration and Certification Research Institute, National Salinity Research Center and It was an agricultural education and extension institute. Most of the extra-organizational relations are related to the Forests, Rangelands and Watershed Management Organization, universities, environment organization, meteorological organization, surveying organization, horticulture deputy of the Ministry of Jihad Agriculture, and scientific associations of agriculture, forestry, rangeland, desert and medicinal plants. Was. The communication network obtained in both types of communication was also of all-round type with acceptable characteristics of acceptable speed in communication, comprehensive communication, relatively good accuracy, and without predetermined structure.

Leisure spaces are the most important functional areas of the city. Convenient access to these spaces can be effective in balancing the soul of citizens. Because the type of access is measured based on the distance and arrival time from one place to another, we can realize the crucial role of the network in this regard.

In this paper which has been done by descriptive analytic method using library and field data collecting, access to leisure spaces in district 9 of Tehran were analyzed in relation to the street network. In this way, access to 11 types of leisure spaces in four land use functions (parks and green space, sports, cultural and entertainment) were evaluated using network analysis.

Levels of access assessment were including the good, average and poor levels and the results showed that access to the sport centers is mostly good and access to the parks, green spaces and catering spaces is relatively good, but access to the cultural spaces is average and poor. In terms of access quality, district 9 of Tehran is divided into two parts, east and west that the western half has better access to leisure spaces than another.

Also, the results of integrated access to leisure facilities map showed that access to leisure facilities along major arterial streets is better than near parts of blocks. This is especially clearly marked in the eastern half of the area. The result of this problem is exclusion the inside parts of neighborhoods and the rise of inequality in access to leisure spaces.

Displaying and quantifying how large-scale climatic signals affect the regional and global climate is one of the issues of interest to researchers. New approch of Network Analysis enables us to study a complex system such as the climate more effectively. In this study, the effect of NAO on precipitation in Iran was investigated using the method of Network Analysis. The data used are daily precipitation and NAO daily indices obtained from ERA-Interim data base. The time period covers the cold months (November, December, Jenury, Februry, March, April) of the years 1979-2016. In order to smooth the daily precipitation data, a weekly moving average was applied to data. A modified Pearson’s cross correlation coefficient  was employed for correction of the bias of traditional Pearson correlation due to many zero-precipitation data. The years of the strong NAO negative and positive phases, NAO- and NAO+, were determined by the frequency of the weekly moving avereage NAO index (WMANAOI) greater that 2 standard deviations ( ), where Sd is the standard deviation. The precipitation network was established based on a constant link density of 0.05 for which vertex degree distribution of network is considered. The later statistics is the covariance between precipitation time series at grid points that show indirectly the effect of the variation of precipitation due to large-scale climate signal. Results demonstrated that Network Analysis method can display and quantified the effect of NAO-and NAO+ on the precipitation of Iran. Degree distribution over the whole duration shows that the most degree distribution is in the northwest, west, southwest and east of Iran. The deserts of Iran that are located in the center of the country have the least degree distribution, and so the least similarity with each other, that are clustered in a group. Also, threshold of network, i.e. , is 0.42 and the histogram of all  has the right skewness. The  is a threshold for selecting the statistically significant  between each two griod points over Iran. The degree distribution for noraml years, with less NAO activities, displays that is 0.42 and degree distribution totally is less than those of NAO+ and NAO-phases. During NAO-, degree distribution is increased in the northwest and southwest of Iran. The  in NAO- is 0.46. During NAO+, the degree distribution is increased in the south of Iran while the threshold of network remain 0.43. Also, the histogram of all  has a positive skewness at NAO+ and NAO-that indicate the strong correlations has positive values. Minimum values of  for the whole period, normal years, NAO+ and NAO-are -0.11, -0.14, -0.3 and -.033, respectively.

Development of industry, agriculture and services, requires training of efficient workforce in technical and vocational fields. Knowing that human activity in these three sectors decreases the environmental quality, dealing with environmental degradation can be achieved by implementing long-term sustainable development education policies. The present study is an applied research and aims to choose the best method for sustainable development education. For this purpose, first, the sustainable development competency criteria for technical and vocational graduates were identified by library studies and three different questionnaires were designed based on them. Then, DEMATEL Technique was used to identify the mutual interactions among the criteria. The obtained results were used for designing a network structure on the fuzzy ANP technique to assign weight to each criterion. Finally, the obtained weights were used to rank and select the best method for sustainable development education based on the TOPSIS technique. Since these techniques cannot resolve the ambiguity and uncertainty of verbal evaluations, the fuzzy triangular numbers were used in all the above-mentioned techniques. The results obtained in this study indicate that self-learning skills and proficiency in the environmental knowledge related to a particular technical and vocational field is the most important sub-criteria of sustainable development competence. Furthermore, group discussions were found to be the most appropriate teaching method for sustainable development education. Due to the importance of sustainable development competence criteria in choosing the right method for sustainable development education, it is necessary to consider all aspects of knowledge, skills, attitude, development and growth, in order to strengthen the environmental attitude and behavior.

Sustainable landscape management formed a hierarchical structure in Iran. That the scale is different at different levels. Various stakeholders at every level have important role for organizations and institutions on the one hand with both their scale and with other stakeholders in the organization linked to other levels. In order to achieve sustainable management of natural resources, water and soil in the areas need organizational participation of all stakeholders. As well as comprehensive management success depends on the organizational integration. This study is of the result project Iranian involvement and empowerment of local communities to approach social networks. The analysis of organizational cohesion and identify key actors in the sustainable landscape management in the Mahalat district of Markazi province. After the discovery of the problems facing the sustainable development of rural and participatory assessment to determine the participatory planning and implementation of policies at the prospect of 5 years, collaborative workshop for organizational stakeholders was held in the district level. In this context, the exchange of information and cooperation ties between stakeholders in organization using a macro-level factors among stakeholders the network and organizational capital were measured in two stages before and after ratification of the visions. Results indicate that the organizational cohesion and reciprocity index links the two legs of medium to heavy conditions improved as well during the first two stages of the centralization of decision-casting has been reduced. These results strengthen cross-sectoral relations towards land management and local sustainable development and decrease the concentration of decision-making and planning in order to achieve sustainable development are emphasized.

Multi-Criteria Decision Making methods have progressed extensively in the past decades and have been applied in various disciplines. Application of them in different fields of geology, especially in assessment of geological hazards which are usually multi-criteria in character, can be very helpful. Studies such as the present study will widen their uses in various fields of geology. Volcanic eruptions in the past centuries attest that stratovolcanoes are more hazardous than other volcanoes and their activity may be disastrous. Hence, in this study, multi-criteria decision making methods of EN-SAW and ANP have been applied to assess and rank the reactivation hazard of Iranian stratovolcanoes (Damavand, Taftan, Bazman, Sahand, Sabalan, Bidkhan and Mesahim) as a case study. So, firstly, the criteria useful in their hazard assessment were selected which include the age of the latest eruption, the presence or absence of tectonic regime creating the volcano, the status of post volcanic activities (e.g. hot springs) and the extent of erosion. Afterwards, they were scored by several experts and lastly, by applying EN-SAW and ANP methods and using Super Decision software, the reactivation hazard scores of these volcanoes were determined and they were ranked. In both these methods, the Damavand volcano ranked first. So, its reactivation potential is higher than other ones and must given the first priority, its threats must be evaluated, its hazard zoning maps should be prepared and (as a kind of monitoring) a seismic station can be established. According to the applied methods, Bazman, Taftan and Sablan volcanoes acquired nearly the same scores. So, ranking after Damavand and it is recommended that they be considered as semi-active (dormant) volcanoes. The condition for Sahand volcano is not clear. However, Bidkhan (in Bardsir town of Kerman) and Masahim (North of Shahrebabak town) both acquired very low scores. So, they are considered as inactive and are not hazardous.

Forests are natural resources most of which are destroyed each year by fire. One way to deal with forest fires is to identify the hot spots in forest fires in the region. This phenomenon destroys hectares of trees, shrubs and plants annually, with an annual average of six to fourteen million hectares of the world's forests estimated to be damaged by fires. This reveals the need for research in this area in order to preserve this invaluable resource. Manesht and Qalarang Protected Area is located in the northern Province of Ilam, covering Chardaval and Ivan. The research aims to assess the level of fire hazard in this protected area using network analysis and geographic information systems. This will apply the most important factors in the process of forest fires according to experts and researchers in these areas, including 9 factors, such as the density of vegetation, rainfall, temperature, slope, aspect, distance from the road, distance from the village height and distance from the river. In the process of modelling for the evaluation of forest fire risk, a sensitivity model network analysis was conducted over three stages and, in this way, the structure of the model was formed in the SuperDecisions software. The matrix of pairwise comparisons was performed using all of 1 to 9 and, then, the super matrix was prepared. Finally, the criteria weighting was determined. The results from this study showed that weighting of criteria for density of vegetation, rainfall, temperature, slope, aspect, distance from the road, distance from the village, elevation and distance from the river to the values were 0.294, 0.226, 0.134, 0.121,0.075,0.051, 0.041, 0.29 and 0.025, respectively; hence, density of vegetation, rainfall, temperature and slope had the greatest weight. Finally, by combining the layers according to the weights obtained in ARC GIS software, a zoning map was prepared. The results showed that the top 50% of regions with dense vegetation, southerly directions and slopes greater than 20 percent are prone to fire hazard. The southerly and easterly directions were determined as receiving the maximum amount of sunlight. Approximately 30 square kilometers (10 percent) of the total area of the 62 square-kilometer area were in the very high risk class (20%) in terms of the probability of fire. So it is essential that measures be taken to prevent the occurrence of fire in these areas. In this research, the zoning map was classified in the five classes of very small, low, medium, high and very high. The results showed that, according to maps from the running model, slopes greater than 20 percent, southerly and easterly directions and areas where vegetation density is over 50 percent are among the areas with high and very high risk of likelihood of fires occurring. It is therefore essential that in these areas the necessary measures be taken to prevent the possibility of fire.