• Geomechanics and Engineering
• /
• v.15 no.3
• /
• pp.811-822
• /
• 2018

Chip size distribution can be used to evaluate the cutting efficiency and to characterize the cutting behavior of rock during cutting and fragmentation process. In this study, a series of linear cutting tests was performed to investigate the effect of cutting conditions (specifically cut spacing and penetration depth) on the production and size distribution of rock chips. Linyi sandstone from China was used in the linear cutting tests. After each run of linear cutting machine test, the rock chips were collected and their size distribution was analyzed using a sieving test and image processing. Image processing can rapidly and cost-effectively provide useful information of size distribution. Rosin-Rammer distribution pamameters, the coarseness index and the coefficients of uniformity and curvature were determined by image processing for different cutting conditions. The size of the rock chips was greatest at the optimum cut spacing, and the size distribution parameters were highly correlated with cutter forces and specific energy.

• Journal of Distribution Research
• /
• v.1 no.2
• /
• pp.141-172
• /
• 1996

This study is to investigate global logistics strategies of Korean electronics companies. in terms of service parts. According to the survey, Korean electronics companies were pursuing multi-level global logistics network such as global, continental, national, regional and service center echelon for improving the efficiency of service parts global logistics. Especially there was a tendency of developing new continental distribution centers. And the companies were exploiting efficiency through inventory control by multi-level echelon, demand forecasting by the product life cycle and supply and service lead time management. But there were some insufficient factors for the efficiency of global logistics operation at the construction of worldwide real time logistics information system and pursuit of the efficiency on the whole network including subcontractors. For the future competitive advantage of the Korean electronics companies, the following are suggested: 1) the establishment of arranged logistics channel adjusting each company's global strategy, 2) the construction of worldwide real time logistics information system, 3) the reengineering of all logistics procedures such as order processing, shipping, inventory control, etc., 4) the enhancement of the ratio of the supply from the external companies and the internal manufacturing subsidiaries at each continent, 5) and the pursuit of operational internalization of external subcontractors.

• International Journal of Quality Innovation
• /
• v.10 no.1
• /
• pp.25-36
• /
• 2009

The purpose of this study is to analyze the efficiency of the service quality activity itself by using the DEA Model, in contrast to previous quality evaluation methods, as an attempt to evaluate the service quality activities of the distribution industry. Furthermore, by complementing the shortfalls of the weighted value of the DEA Model, it recommends a DEA/PS Model that is appropriate in the evaluation of service quality activities. Based on this model, the study proposes the SQAE Model, an evaluation tool to complement the traditional measuring method. According to the results of the analysis of 18 sample distribution businesses, there was a discrepancy by business in the results of the Traditional Scoring System and the Evaluation Measuring System. Therefore, it is most desirable to not only be active in service quality activities but also increase efficiency at the same time.

• Particle and aerosol research
• /
• v.10 no.4
• /
• pp.155-162
• /
• 2014

The internal temperature will change depending on operation conditions and material of cyclone dust collector. This study compares the results of collection efficiency and temperature distribution on the different heat flux at wall of dust collector. The previous researcher's experiment results were used to confirm the reliability of CFD(Computational Fluid Dynamics) model. Based on this verified CFD model, we extended the analysis on the cyclone dust collectors. In CFD study, we used RNG k-epsilon model for analysis of turbulence flow, fluid is air, the velocity at inlet is 10 m/s, the temperature of air is $600^{\circ}C$. Because of the difference of outer vortex and inner vortex temperature, the collection efficiency will reduce with the increase of heat flux, showed the highest collection efficiency at heat insulation.

• Journal of the Korean Society of Safety
• /
• v.13 no.4
• /
• pp.155-161
• /
• 1998

Recently, there are widely needs of small scale electrostatic precipitator(ESP) in machine shop and other factories. Since the space of such factories is limited, the improvement of collection efficiency is predominant subject. In this study, we examine the influence of distribution of wind velocity and oil mist concentration inside the ESP in order to improve the performance of the ESP. The distribution of wind velocity and mist concentration is measured respectively in a cross-sectional plane of the ESP. The former is controlled by using a louver which is placed in front of an ionizer and the latter is controlled by lengthening the pipe of entrance of the ESP in order to have plenty of time that mist is dispersed evenly. It is shown that the uniformity of distribution of wind velocity and mist concentration inside the ESP can be getting by adopting a louver with proper shape and lengthening the pipe of entrance and is also contributed to collection efficiency considerably.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.13 no.4
• /
• pp.689-696
• /
• 1989

In this experimental study, relative particle size distribution was measureed at the inlet and outlet of the slit impactor using the particle sizer. The imployed measuring method of the size distribution was different from the conventional method. This measurement system has the advantage of obtaining the particle collection efficiency for various particle size easily and at once compared with other methods. The effects of jet to plate distance and Reynolds number on the characteristic impactor efficiency curves have been studied. In the results of this experiment, the increment of collection efficiency was observed as Reynolds number increases in the case of S/W = 1/2 but was very slight. The influence of S/W is more remarkable than that of Reynolds number on the particle collection efficiency.

• Communications for Statistical Applications and Methods
• /
• v.5 no.1
• /
• pp.231-238
• /
• 1998

A two stage shrinkage testimator for the mean of an exponential distribution is considered with the assumption that an initial estimate of the mean is available. Mean squared error(MSE) of testimator and its relative efficiency (to usual single sample mean) are briefly reviewed. It is shown that relative efficiency depends only on the ratio of true mean value and its initial estimate.

• Journal of Distribution Science
• /
• v.13 no.7
• /
• pp.41-51
• /
• 2015

Purpose - This study analyzes loading efficiency by loading pattern for package standardization and reduction of logistics costs, along with the creation of revenue for the revenue review panel (RRP) of Membership Wholesale Clubs (MWC). The study aims to identify standard dimensions that can help improve the compatibility of the pallets related to display patterns preferred by the MWC and thereby explore ways to enhance logistics efficiency between manufacturers and retailers through standardization. Research design, data, and methodology - The study investigates and analyzes the current status based on actual case examples, i.e., manufacturer A and Korea's MWC (A company, B company, and C company), and thus devises improvement measures. To achieve this, the case of manufacturer A delivering to MWC was examined, and the actual pallet display patterns for each MWC were investigated by visiting each distribution site. In this study, TOPS (Total Optimization Packaging Software, USA) was used as the tool for pallet loading efficiency simulations the maximum allowable dimension was set to 0.0mm to prevent the pallet from falling outside the parameters, and the loading efficiency was analyzed with the pallet area. In other words, the study focused on dimensions (length x width x height) according to the research purpose and thereby deduced results. Results - The analysis of pallet loading patterns showed that the most preferred loading patterns for loading efficiency according to product specification, such as pinwheel, brick, and block patterns, were used in the case of the general distribution products, but the products were configured with block patterns in most cases when delivered to MWCs. The loading efficiency by loading pattern was analyzed with respect to 104 nationally listed standard dimensions. Meanwhile, No.51 (330 × 220mm) of KS T 1002 (1,100 × 1,100mm) was found to be the dimension that could bring about an improved loading efficiency, over 90.0% simultaneously in both the T-11 and T-12 pallet systems in a loading pattern configuration with the block pattern only, and the loading efficiency simulation results also confirmed this as the standard dimension that can be commonly applied to both the T-11 pallet (90.0%) and the T-12 pallet (90.7%) systems. Conclusions - The loading efficiency simulation results by loading pattern were analyzed: For the T-11 pallet system, 17 standard dimension sizes displayed the loading efficiency of 90.0% or more as block patterns, and the loading capacity was an average of 99.0%. For the T-12 pallet system, 35 standard dimension sizes displayed the loading efficiency of more than 90% as block patterns (the average loading efficiency of 98.6%). Accordingly, this study proposes that the standard dimensions of 17 sizes with the average loading efficiency of 99.0% should be applied in the use of the T-11 pallet system, and those of 35 sizes with the average loading efficiency of 98.6% should be reviewed and applied in the use of the T-12 pallet system.

• Journal of environmental and Sanitary engineering
• /
• v.14 no.4
• /
• pp.69-76
• /
• 1999

This research was carried but to investigate the characteristics of mist removal with the change of operating conditions in the plasma reactor of impulse streamer corona based on the distribution of particle size measured by laser diffraction spectrometers. The operating conditions in this experiment were power of impulse streamer corona, gas velocity, collection time, and SOx/NOx concentration. The collection efficiency T(d) was estimated by distribution of particle size in the collection zone through the advanced model.

• Communications for Statistical Applications and Methods
• /
• v.11 no.3
• /
• pp.435-446
• /
• 2004

In this paper we introduced a new score generating function for the rank dispersion function in a multiple linear model. Based on the new score function, we derived the asymptotic relative efficiency, ARE(11, rs), of our score function with respect to the Wilcoxon scores for the generalized F distributions which show very flexible distributions with a variety of shape and tail behaviors. We thoroughly explored the selection of r and s of our new score function that provides improvement over the Wilcoxon scores.