• Journal of Korean Institute of Industrial Engineers
• /
• v.21 no.3
• /
• pp.345-356
• /
• 1995

The aim of this paper is to analyze the batch service queueing model M/M(a, b ; ${\mu}_k/1$) under general bulk service rule with mean service rate ${\mu}_k$ for a batch of k units, where $a{\leq}k{\leq}b$. This queueing model consists of the two-dimensional state space so that it is characterized by two-dimensional state Markov process. The steady-state solution and performane measure of this process are derived by using Matrix Geometric method. Meanwhile, a new approach is suggested to calculate the two-dimensional traffic density R which is used to obtain the steady-state solution. In addition, to determine the optimal service initiation threshold a, a decision model of this queueing system is developed evaluating cost of service per batch and cost of waiting per customer. In a job order production system, the decision-making procedure presented in this paper can be applicable to determining when production should be started.

• Journal of Biosystems Engineering
• /
• v.3 no.2
• /
• pp.114-125
• /
• 1978

The use of petroleum fuels in grain drying causes problems of high cost and management. To solve these problems, it is required to study on soLar energy as an alternative to petroleum fuels for grain drying. The purposes of this study were to find out the optimum received area and air flow rate of a flat-plate solar air collector for grain drying and to assess its effects on grain drying with a small grain bin. The results of this study are summarized as follows ; 1. The calculated optimum tilt angles of the collector in the summer and autumn drying seasons were 20 and 50 degress, respectively, in suwon area. 2. The outlet temperature of the collector was $36^\circ C$ on the daily average with the maximum of $36^\circ C$ at 12:00 o clock. Solar radiation on the collector surface was 1.04 ly( 1 langley = 1 cal/$cm^2$) per minute on the daily average and 1.30 ly per minute on the maximum at 11:00am. The thermal efficiency of the collector was 62.4 percent on the daily average, and the air flow-rate per unit receiving are was 1.03 $m^3$/min/$m^2$.4. The calculated optimum receiving area and the air flow-rate per unit cubic volume for paddy in autumn drying season was 2 $m^2$ and 2$m^3$/min , respectively. 5. not significantly difference in the collector efficiency was appeared between the rotating and fixed type of solar collector. 6. For drying of wheat with 0.6 meter of the depth in the bin, approximately 9 hours were required to reduce the moisture content from 21.6% to 13% with air follow rate of 5 $m^3$/min an initial moisture per cubic meter of wheat and with air temperature of $52^\circ C$. 7. In the drying test of rough rice with a turning operation in a grain bin approximately 21 hours were required to reduced the moisture from 21% to 14.5% with airflow rate of 2 $m^3$/min per cubic meter of rice and the air temperature of $43.5^\circ C$. 8. Over-drying at the bottom and less -drying at the top of the grain mass was resulted from the high -temperature of drying air which was obtained from the flat-plate solar collector in this test. An appropriate operation should be prepared for the uniform moisture of the grain in the bin.

• Asian-Australasian Journal of Animal Sciences
• /
• v.7 no.1
• /
• pp.49-55
• /
• 1994

This study was conducted to compare the of rearing native and cross-bred dairy cows and returns received from them. For this purpose, 144 cows of 132 household from 24 villages were randomly selected. of them, 96 were native cows and 48 were cross-bred cows. The study revealed that among the structure of cost components, labour charge occupied the major share in the total cost of milk production per litre. The total cost of rearing native and cross-bred cows was Tk. 14,155 and Tk. 19,854 per annum, respectively. The average net cost of milk production per litre was Tk. 14.12 for native cows and Tk. 0.52 and for cross-bred cows were Taka 3.40. The benefit-cost ratio of milk per litre was higher (1:1.33) in cross-bred cows than native ones (1:1.04). The study further showed that in comparing with bulk line cost, the price of milk per litre received by the farmers was higher in cross-bred cows than native cows. Therefore, the study recommends dairying with cross-bred cows as encouraging and viable commercial enterprise in Banfladesh.

• Proceedings of the Ginseng society Conference
• /
• 1980.09a
• /
• pp.39-47
• /
• 1980

The harvesting and export of Canadian ginseng from the cool, shady hardwood forests of southern Canada can be traced to 1796. Because of its high dollar value and diminishing woodland supplies it was decided in 1896 that it should be cultivated under wood lath screens. Present day economics dictate changes in production techniques to allow for a decreasing supply of expensive labour. Traditional wooden lath screens have a surface area of wood of 70 per cent and permit light penetration of only about 18 per cent. Experimental woven black polypropylene shade has an estimated surface area of 72 per cent and permits light pentration of about 28 per cent. While differences in air and leaf temperatures under the two shade structures can be measured it is doubtful if these are great enough to cause differences in plant growth under the two structures. Shade grown ginseng had a low fresh and dry weight and total chlorophyll content (ratio of a to b was 3 to 1) comparable to other shade species. There was no differences in fresh and dry weight and chlorophyll content of leaves from plants grown under the two shade structures. Maximum net photosynthesis of leaves was 0.175 g $CO_2\;m^{-2}\;hr^{-1}$ and light saturation level was about $200{\mu}E\;m^{-2}\;s^{-1},$ or about 10 per cent of full sunlight.

• Journal of Yeungnam Medical Science
• /
• v.6 no.1
• /
• pp.151-163
• /
• 1989

Nerve conduction studies help delineate the extent and distribution of the neural lesion. The nerve conduction was studied on upper(median, ulnar and radial nerves) and lower(personal, posterior tibial and sural nerves) extremities in 83 healthy subjects 23 to 66 years of age. and normal values were established(Table 1). The mean motor terminal latency (TL) were : median. 3.6(${\pm}0.6$)milliseconds ; ulnar. 2.9(${\pm}0.5$) milliseconds ; radial nerve. 2.3(${\pm}0.4$) milliseconds. Mean motor nerve conduction velocity(MNCV) along distal and proximal segments: median. 61.2(${\pm}9.1$) (W-E) and 57.8(${\pm}13.2$) (E-Ax) meters per second ; ulnar. 63.7(${\pm}9.1$) (W-E) and 50.(${\pm}10.0$) meters per second. Mean sensory nerve conduction velocity(SNCV) : median. 34.7(${\pm}6.7$) (F-W), 63.7(${\pm}7.1$) (W-E) and 62.8(${\pm}12.3$) (E-Ax)meters per second ; ulnar. 38.0(${\pm}6.7$)(F-W), 63.4(${\pm}7.5$) (W-E) and 57.0(${\pm}10.1$) (E-Ax)meters per second ; radial, 45.3(${\pm}6.8$) (F-W) and 64.2(${\pm}11.0$) (W-E) meters per second ; sural nerve, 43.4(${\pm}6.1$) meters per second. The amplitudes of action potential and H-reflex were also standardized. Mean H latency was 28.4(${\pm}3.2$) milliseconds. And. the fundamental principles, several factors altering the rate of nerve conduction and clinical application of nerve stimulation techniques were reviewed.

• Asian-Australasian Journal of Animal Sciences
• /
• v.15 no.10
• /
• pp.1453-1457
• /
• 2002

The experiment was conducted to find out the effect of 4 feeding systems on growth, feed intake, eating behavior, lactation performance, gestation period, post-partum heat period, conception rate and parasitic infestation of Black Bengal goat. Twenty four does of approximately 1 year of age were randomly selected for 4 treatment (feeding systems) groups having 6 replications in each. Treatments were stall feeding ($T_1$), tethering ($T_2$), restricted grazing ($T_3$) and grazing ($T_4$). $T_1$ group was housed continuously and adequate amounts of natural grass were supplied for ad libitum feeding. $T_2$ group was tethered for grazing natural grass from 8 a.m. to 4 p.m. being moved at one hour intervals. Goats of $T_3$ group were allowed grazing from 8 a.m. to 1 p.m. $T_4$ group was grazed from 8 a. m. to 4 p.m. Concentrate supplement was given at the rate of 150 g per day per goat for all of the treatment groups. Duration of experiment was 219 days. Daily live weight gain was significantly (p<0.05) higher in case of stall fed goats than that of others. DM intake also significantly (p<0.05) differed among the treatment groups and was 3.40 3.95, 3.76 and 4.05 per cent of their live weight for stall feeding, tethering, restricted grazing and grazing groups, respectively. Rate of rumination was significantly (p<0.05) higher in case of tethering group of goats than that of others. Birth weight of kids, milk yield, lactation period and post-partum heat period were significantly higher in case of stall fed goats than others. Tethering group showed significantly (p<0.05) higher litter size than others. Infestation rate of Fasciola was significantly (p<0.05) higher in the grazing group. In conclusion, it may be stated that among these feeding groups overall performance of stall fed goats was more satisfactory, and that the tethering group showed better performance than the others.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.40 no.1
• /
• pp.39-43
• /
• 1995

In the culture of Vinyl mulching and Non mulching, growth, yield, and cotton hair's growth are studied at the different planting density to get a basic material for cotton culture and high yield bumper crop in the region of the South. And the results are following. Vinyl mulching is the best one at the strength, the number of boll bearing branches, the num-ber of bolls, the number of bolls per $m^2$ and all the other characters. Vinyl mulching and Non mulching have the greatest number of bolls per $m^2$ at the planting density of 70${\times}$10cm. Vinyl mulching has the highest seed cotton yield and the highest seed cotton yield per boll. Especially when planted at the density of 70${\times}$l0cm, Vinyl mulching and Non mulching have the highest seed cotton yield. Vinyl mulching's value is accepted in fiber length and lint percentage, the wider spacing in the row is, the longer fiber length is.

• Journal of Environmental Health Sciences
• /
• v.27 no.4
• /
• pp.15-24
• /
• 2001

The objective of this study it to evaluate the microbial safety in rapid sand filters adapted in most drinking water treatment plants. The potential pathogens to cause water quality problems Are presumed to be Giardia and Gryptosporidium. They look like particles in view of their size. It has been reported that if the number of particles (larger than 2 ${\mu}{\textrm}{m}$ in water) is less than 100 per mL and its turbidity is below 0.1 NTU, it is considered as a safe water in terms of pathogens. In order to achieve such a good water quality. filter-aids (chemicals) were added to the inlet-channel of filter and their effectiveness was evaluated on the basis of water quality factors such as turbidity and particle counting. This study was conducted in she three steps of experiment: jar test. pilot plant test and real water treatment plant test (P plant in seoul). The experiment reult of the P water treatment showed that cationic polyamine was the most effective in the removal of particles and turbidity at the does of 0.25 mg/L. The turbidity without filer-aids showed in the range of 0.12 ~0.17 NTU during filtration and 0.14 NTU on the average. However. with addition of polyamine, the turbidity represented below(or less than) 0.1 NTU after 20 min in the start of filtration and kept 0.08 NTU on the average. On the other hand, as for number of particles, while no filter-aids led to the range of 111 ~270 per mL and 190 on the average, addition of polydmine led to 113 per mL on talc average, and kept below100 per mL after 20 min in the start of filtration.

• Journal of Korea Water Resources Association
• /
• v.43 no.11
• /
• pp.957-965
• /
• 2010

The municipal water is directly related to the people's quality of life. To examine and implement reasonable water policies including management of the water demand and economically sound investment decisions, it is essential to estimate the conceptually correct and empirically valid economic value of water. This study attempts to estimate the consumer surplus and economic value of municipal water which is supplied to 16 cities in Korea using demand curve approach. The results indicate that the consumer surplus and economic value of municipal water in 2009 are estimated as KRW 1,180.7 per $m^3$ and KRW 1,812.8 per $m^3$, respectively. The economic values of municipal water in 16 cities range from KRW 1,082.7 per $m^3$ to KRW 3,268.6 per $m^3$. Moreover, the economic value of non-residential water is higher than that of residential water in all cities, and the economic value of water is higher than the present price of water. This study is expected to provide policy-makers with useful information to assess a policy and to evaluate the price of water.

• Korean journal of applied entomology
• /
• v.48 no.4
• /
• pp.503-508
• /
• 2009

Biological-control-based-integrated-pest-management of major pests occurring on sweet pepper in greenhouse during summer season was tried. As many as 2.1 Orius laevigatus per $m^2$ were released in two times on June 6 and 19, and the population of thrips was kept under control and accordingly the damage was negligible throughout the season. To control aphids, a total of 0.8 Aphidius colemani per $m^2$ were released in four times, 0.2 of them at a time, flonicamid on May 14 and July 18 and pymetrozine on June 14 and September 4 were sprayed on the spots of high aphid occurrence to reduce the release of the wasp, and the density of aphids was kept under control. Whitefly was controlled successfully by releasing a total of 343.4 Amblyseius swirski per $m^2$ in nine times, 38.1 of them at a time, from May 9 until November 12 and dinotefuran was sprayed on November 12 when the density of whitefly increased up to 200 per trap. Tetranichus kanzawai was controlled by both Phytoseiulus persimilis which was released a total of 44.4 per $m^2$ in five times 8.9 of them at a time from May 23 to September 10, and the A. swirski which was released for the control of whitefly.