For safe disposal of radioactive wastes, accurate analysis of nuclear isotopes is important. It is known that there are 14 nuclides that have to identify nuclide-specific concentration levels. 63Ni, one of non-volatile nuclear isotopes which is included in those 14 nuclides, has to follow chemical separation for exact analysis. As various analysis methods were developed, various methods for analyzing 63Ni also emerged. Past method has used measurement specimens of 59Ni, after 59Ni measurement has been done. It used HClO4, known as strong oxidizing agent, to dissolve DMG, an organic substance used to form 59Ni precipitates. Nowadays, we analyze 59Ni and 63Ni simultaneously, which enables short analysis time, without use of HClO4. But high accuracy is just as important as short measurement time and efficiency. So, this paper compare 63Ni specific activity value used new method with the value, past method used, using real sample’s data. As a result, all sample data from new method’s relative 63Ni specific activity is within the uncertainty range of past ones based on past specific activity value. Consistency of new method’s result and past method’s data increased the reliability of the data and accuracy of those methods.

In order to indirectly evaluate the inventory of difficult-to-measure (DTM) nuclides in radioactive waste, the scaling factor method by key nuclide has been used. It has been usually applied to low-and intermediate-level dry active waste (DAW), and the tolerance of 1,000% margin of error in the US, that is the factor of 10, is applied as an allowable confidence limits considering the inhomogeneity of the waste and the limitation of sample size. This is because the scaling factor method is based on economic efficiency. Confidence limits is the uncertainty (sampling error) according to predicting the mean value of the population by the mean value of the sample at 95% confidence level, reflecting the limitations of sample size (representation) with the standard deviation. If the standard deviation is large, the sample size can be increased to satisfy the allowable confidence limits. In the new nuclear power plants, the concentration of cesium nuclide (137Cs) in radioactive waste tends to be very low due to advances in nuclear fuel and reactor core management technology, which makes it very difficult to apply cesium as a key nuclide. In addition, it is inevitable to apply the mean activity concentration method, which reasonably and empirically derives the concentration of DTM nuclides regardless of key nuclide, when the correlation between key and DTM nuclides is not significant. The mean activity method is a methodology that applies the average concentration of a sample set to the entire population, and is similar to applying the average concentration ratio between key and DTM nuclides of a sample set to the population in the scaling factor method. Therefore, in this paper, the maximum acceptable uncertainty (confidence limits) at a reasonable level was studied when applying the mean activity concentration method by arithmetic mean unlike the scaling factor method which usually uses the geometric mean method. Several measures were proposed by applying mutatis mutandis the acceptable standard deviation in radiation measurement and the factor of 10 principle, etc., and the appropriateness was reviewed through case analysis.

The smoke emission of biodiesel fuel was reduced remarkably in comparison with diesel fuel, that is, it was reduced approximately 36% at 2000rpm, full load condition. And, power, torque and brake specific energy consumption showed no significant differences. However, NOx emission of biodiesel fuel was increased compared with commercial diesel fuel. Also, the effects of exhaust gas recirculation(EGR) to reduce the NOx emission has been investigated. It was found that simultaneous reduction of smoke and NOx was achieved with biodiesel fuel(20vol-%) and cooled EGR method(10∼15%).

This study tried to focus on nontraditional job that has not been studied in terms of the subjects associated with MSDs(Musculoskeletal Disorders). Specifically, dental procedure was the job to be analyzed in this study. An alternative method as well as a traditional method for viewing teeth while performing simulated dental procedures. Four graduated students did both methods(direct view and indirect view) as the subjects in this study. The method based on indirect view used a video camera and monitor to view the teeth. The experiment was conducted five times for each subject. The major findings in this study were as follows; 1) Job speed was increased with the repetitions for both methods, 2) Difference of Neck flexion between direct and indirect methods was statistically siginificant(Neck flexion for indirect method was dramatically decreased), 3) Difference of job speed between direct and indirect methods was statistically significant(Job speed for direct method was faster than that of indirect method), 4) Difference of error rate between direct and indirect methods was statistically significant(error rate for direct method was lower than that of indirect method), 5) Even though indirect method did not provide better performance in terms of job speed and error rate yet, it seemed to need a trade-off between two methods in the future since indirect method provided better working postures than that of direct method.

  The National Wealth Survey Method has been used to estimate capital stocks in Korea by the Korea National Statistical Office in every 10 years. However, this method requires huge amount of time and money. Since the Benchmark Year Method also has similar