• International Journal of Reliability and Applications
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• v.16 no.1
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• pp.15-26
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• 2015

Present study investigates the fuzzy reliability of some systems using intuitionistic fuzzy Weibull lifetime distribution, in which the lifetime parameters are assumed to be fuzzy parameter due to uncertainty and inaccuracy of data. Expressions for fuzzy reliability, fuzzy mean time to failure, fuzzy hazard function and their ${\alpha}$-cut have been discussed when systems follow intuitionistic fuzzy Weibull lifetime distribution. A numerical example is also taken to illustrate the methodology to calculate the fuzzy reliability characteristics of systems.

• Journal of applied mathematics & informatics
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• v.40 no.1_2
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• pp.205-213
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• 2022

In this paper we give a simple and direct proof of an Euler integral representation for a special class of _q+1F_q,k k-hypergeometric functions for q ≥ 2. The values of certain ₃F_2,k and ₄F_3,k functions at $x=\frac{1}{k}$, some of which can be derived using other methods. We may conclude that for k = 1 the results are reduced to [3].

• The Korean Journal of Applied Statistics
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• v.29 no.3
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• pp.487-503
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• 2016

Urban-to-rural migration for farming has recently emerged as a new way to vitalize rural economies in a fast-aging rural Korea. In this paper, we analyze the 2013 data of returning farmers with statistical network methods. We identify urban to rural migration hubs with centrality measures and find migration trends based on regional clusters with similar features via statistical network models. We also fit a latent distance model to investigate the role of distance in migration.

• Communications for Statistical Applications and Methods
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• v.22 no.5
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• pp.435-443
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• 2015

Two phase sampling design is useful to increase estimation efficiency using deep stratification, improved non-response adjustment and reduced coverage bias. The same sampling units are commonly used for the first and the second phases in complex two-phase sampling design. In this paper we consider a sampling scheme where the first phase sampling units are clusters and the second phase sampling units are list samples. Using selected clusters in first phase requires that we list up elements in the selected clusters from the first phase and then use the list as a secondary sampling frame for the second phase sampling design. Then we select second phase samples from the listed sampling frame. We suggest an estimator based on the complex two-phase sampling design with different sampling units of each phase. Also the estimated variances of the estimator obtained by using classic and replication variance methods are considered and compared using simulation studies. For real data analysis, 2010 Korea Farm Household Economy Survey (KFHES) and 2011 Korea Agriculture Survey (KAS) are used.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.10a
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• pp.153-161
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• 2008

Agriculture and forest are basis for livelihood in Nepal while both sectors constitute around 40 percent of the national product and over two-thirds of the economically active population is dependent on agriculture. However, radical changes in land use, depletion in crops production and food availability are major threats due to loss of soil fertilityand severe environmental degradation. In this study, we used time series data from 1986/87 to 2005/06 about food crop production and population published by Government of Nepal, Ministry of Agriculture and Cooperatives and Central Bureau of Statistics. Descriptive statistics and ArcGIS were used to assess and map the food security status of Nepalese Terai based on the local food demand and supply system. Food supply to demand ratio(FSDR) was the main idea of assessment. Our results showed that out of 20 districts, only 8 districts were categorised under secured food districts whereas 5 districts were still under food unsecured situation. The analysis further revealed that 7 districts had faced food deficit more than 8-16 times during the last 20 year periods. Data further showed that there was surplus food supply relative to the requirements dictated by FSDR. However, the average FSDR was less than 1.2(less than 20% surplus) exploring fact that most of the districts were not producing sufficient food to cope up the food shock and after 1995 it was relatively stagnant. Our prediction reveals that food supply in Terai even in the future would remain at almost the same level as now, and there will not more than 16-17% surplus by 2021 considering medium vibrant population growth. The findings thus, indicate that Terai may not be a food secure region in the future, even though the region is considered as a food storage house of Nepal. In addition, this paper suggests ways to make future comprehensive case studies more widely comparable in Terai, Nepal.

• Journal of the Korean Statistical Society
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• v.31 no.2
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• pp.143-152
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• 2002

In an effort to make a right choice among ratio estimation strategies and PPS sampling strategies, we conduct an empirical investigation of the relative performances of three ratio estimation strategies and four PPS estimation strategies using a set of 12 natural populations. The quality of a strategy is measured in the traditional way, namely with the consideration of efficiency, achieved coverage rate of the nominal 99% confidence interval and approach to normality (asymmetry).

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.254-261
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• 2000

Soil chemical properties, relief of field surface, SPAD values and grain yield were investigated in a 0.5ha paddy field in 1999 to obtain basic field information for precision agriculture. Descriptive statistics of field information showed that the coefficient of variation ranged from 1.63% to 38.7%. Field information showed a high spatial dependence for within paddy field. The ranges of spatial dependence were from 15m to 60m, respectively. Kriged maps enable the visualization and comparison the spatial variability of field information. The causes of spatial variability of the field information could be explained rationally by a field management map. Grain yield was negatively correlated with pH, relief values, whereas, was positively correlated with total C, total N, C/N ratio, mineralizable N, available P and exchangeable K, Ca at the significant level of 1 %.

• Journal of Agricultural Extension & Community Development
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• v.16 no.4
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• pp.967-992
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• 2009

The purpose of this study is to segment the social awareness on the function of public benefit of agriculture and rural areas by socio-economic and action/attitude characteristics, and to identify the influential variables in social awareness. The nationwide survey of 1,200 adults aged over 20 was conducted, and the data was analyzed by PASW statistics 17.0. One of the awareness variables was the degree of the consent to the preservation of the public beneficial function. This variable was segmented by the interest on related information, the criteria of buying agricultural products, occupation and age. And the other awareness variable was the willingness to pay for the preservation of the public beneficial function. This variable was segmented by the education, occupation, income and the experience of living in rural areas. According to the results, some suggestions for improving the social awareness on the public beneficial function of agriculture and rural areas were discussed.

• Journal of agriculture & life science
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• v.45 no.6
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• pp.291-301
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• 2011

This study is based on the diagnosis process on agricultural production cost survey, which is one of the most representative public statistics of agricultural sector in Korea. The diagnosis were performed by employing the quantitative and qualitative approaches with the official guideline provided by the Ministry of Statistics. The various results were produced from the aspects of exactness, relevance, timeliness, accessibility, and comparability, which were based on the qualitative approaches including focus group interview (FGI) with professional users. The results from statistical portfolio analysis implies that the first priority to improve the statistics is given to 'satisfaction level corresponding to user cost' and 'offering sufficient explanation'. The comprehensive results, discussed with the administrative office, are summarized into the following two major points. First, classification of the detailed items should be improved to avoid users' confusion. However, the re-classification need to be professionally reviewed with the relevant administrative office such as Rural Development Administration, producing similar statistics. Second, the KOSIS system is found to be constantly upgraded to improve the users' convenience.

• Korean Journal of Mathematics
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• v.30 no.2
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• pp.263-281
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• 2022

The main aim of this paper is to discuss two different types of soft hemirings, soft intersection and soft union. We discuss applications and results related to soft intersection hemirings or soft intersection k-ideals and soft union hemirings or soft union k-ideals. The deep concept of k-closure, intersection and union of soft sets, ∧-product and ∨-product among soft sets, upper 𝛽-inclusion and lower 𝛽-inclusion of soft sets is discussed here. Many applications related to soft intersection-union sum and soft intersection-union product of sets are investigated in this paper. We characterize k-hemiregular hemirings by the soft intersection k-ideals and soft union k-ideals.