• Journal of Broadcast Engineering
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• v.15 no.6
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• pp.845-852
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• 2010

Collecting statistics from client requests, the broadcast server partitions data items into hot and cold-item sets with the optimal cut-off point. Hot items are broadcast periodically with periods based on their access probabilities. In a time slot with no hot items scheduled, the server broadcasts a proper cold item considering the waiting time and the number of outstanding requests. We analyze the optimal the cut-off point by calculating average response time as a function of the cut-off point. Simulation results show that our proposed algorithm outperforms existing methods in various circumstances.

• Explosives and Blasting
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• v.31 no.1
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• pp.33-40
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• 2013

Carinthian cut and cover tunnelling method which combines cut & cover and NATM tunnel excavation method has increased the interest. Design and construction of arch concrete have been increased, but there is no applicable standards for arch concrete. Therefore, in this study numerical analysis was performed to propose standards for the Carinthian tunnelling method considering a variety of conditions such as ground conditions, tunnel overburden thickness, thickness of backfill, and overburden surface slope angle changes, linear regression equations derived to classify and organize a rational, economical, and safe Carinthian cut and cover tunneling method based proposed.

• Restorative Dentistry and Endodontics
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• v.36 no.6
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• pp.477-482
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• 2011

Objectives: The purpose of this study was to compare the microshear bond strength (uSBS) to enamel prepared with different burs and to determine what type of bur were chosen when a self-etching primer adhesive was used. Materials and Methods: Enamel of forty-two human molars were used. They were divided into one of six groups (n = 7), Group 1, coarse (125 - 150 ${\mu}m$) diamond bur; Group 2, standard (106 - 125 ${\mu}m$) diamond bur; Group 3, fine (53 - 63 ${\mu}m$) diamond bur; Group 4, extrafine (20 - 30 ${\mu}m$) diamond bur; Group 5, plaincut carbide bur (no. 245); Group 6, cross-cut carbide bur (no. 557). Clearfil SE Bond and Clearfil AP-X (Kuraray Medical Inc.) was bonded to enamel surface. The bonded specimens were subjected to uSBS testing. Results: The uSBS of Group 4 was the highest among groups and it was significantly higher than that of Groups 1, 2, 3, and 6 (p < 0.05), but it was not significantly different from that of Group 5. Conclusions: Different burs used on enamel surface affected the microshear bond strengths of a self-etching primer adhesive to the enamel surface. In the case of Clearfil SE Bond, extrafine diamond and plain-cut carbide bur are recommended for bonding to enamel.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.6
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• pp.714-719
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• 2011

The surface roughness depending on the machining method is very important because is produce a finished product through riveting, sealing, bonding, and special paint in order to curb the turbulence and air resistance which occur between the sheets. Aluminum alloy 2024 which is widely used for interior and exterior material of aircraft are tested. Jin-young JW-60C wire cutting machine was used in this experiment. In this paper, the experimental investigation has been performed to find out the influence of the surface roughness and surface shape characteristics on the wire-cut EDM of discharge energy in aluminium alloy 2024. The selected experimental parameters are peak current, no-load voltage, off time and feed rate. The experimental results give the guideline for selecting reasonable machining parameters. The high discharge energy on the idle time, almost no change in surface roughness can be seen.

• Horticultural Science & Technology
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• v.16 no.3
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• pp.366-369
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• 1998

To lesson economical loss induced by fumigation in importing country when cut roses are exported, effects of several fumigation temperature, treatments of cut stems (dry or wet), methyl bromide (MB) concentrations, and fumigation periods on the quality of cut roses were investigated. According to results, the most important factor affecting the quality of cut rose was found to be fumigation temperature. When fumigated at $5^{\circ}C$, cut roses showed no chemical damages, e.g., tip burn or bent neck, and maintained their quality for the same duration as that of control, regardless of MB concentrations or treatments of cut stems. However, phytotoxicity by MB increased and vase life of cut rose was shortened as fumigation temperature increased. Timing of fumigation also appeared to be an important factor affecting the quality of cut roses of which phytotoxicity by MB was not observed and thier vase life was not shortened, even if MB was treated up to $40g{\cdot}m^{-3}$, when cut roses were fumigated at $5^{\circ}C$ on the day of harvesting. On the other hand, the degree of damage of cut flowers by fumigation methods or MB concentraions was not consistent with changes in fumigation temperature.

• Journal of Applied and Pure Mathematics
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• v.4 no.1_2
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• pp.79-84
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• 2022

We have observed that there exist certain fuzzy topological spaces with no fuzzy minimal open sets. This observation motivates us to investigate fuzzy topological spaces with neither fuzzy minimal open sets nor fuzzy maximal open sets. We have observed if such fuzzy topological spaces exist and if it is connected are not fuzzy cut-point spaces. We also study and characterize certain properties of fuzzy mean open sets in fuzzy T₁-connected fuzzy topological spaces.

• Korean Journal of Human Ecology
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• v.4 no.1
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• pp.36-45
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• 2001

This study was performed to determine the changes of maternal iron status during pregnancy cross sectionally, and to evaluate the appropriateness of the cut-off points of hemoglobin (Hb). hematocrit (Hct), serum transferrin receptor (sTfR) and sTfR : ferritin ratio for assessing iron deficiency status based on serum ferritin level (< 12${\mu}g$/L). Serum Hb concentrations in the first trimester were significantly higher (p < 0.05) than those in the second and third trimester. Serum levels of iron and ferritin in the third trimester were significantly lower (p < 0.05) than those in the first and second trimester. On the other hand, sTfR:ferritin ratios in the third trimester were significantly higher (p < 0.05) than those in the first and second trimester. sTfR concentrations did not change significantly during pregnancy. The appropriate cut-off points of Hb were 11.5g/dL for whole period of pregnancy. 12.0g/dL for 1st trimester. and 11.5g/dL for both 2nd and 3rd trimester. The good cut-off points of Hct were 34% for whole period of pregnancy. 36% for 1st trimester. and 34% for both 2nd and 3rd trimester The suitable cut-off points of TIBC were 400${\mu}g$/dL for whole period of pregnancy. 360${\mu}g$/dL for 1st trimester, and 400${\mu}g$/dL for both 2nd and 3rd trimester. Any cut-off point of sTfR could not be selected because of its low sensitivity and specificity. The proper cut-off point of sTfR : ferritin ratio was 600 or 650 for all the periods determined except the first trimester. In conclusion, there were no reliable cut-off levels of sTfR and those of sTfR : ferritin ratio showed low specificity. The cut-off values of Hb and Hct for assessing iron deficiency were slightly higher than the values used to evaluate anemia. Thus, if appropriate cut-off levels were applied, Hb. Hct, or TIBC might be useful indices for evaluating iron deficiency as well as anemia.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.3
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• pp.164-170
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• 2016

A proposed pneumatic cylinder-driven roll feeder and an air press were designed to be operated automatically by a PLC. The accuracy of the intermittent feed pitch of the roll feeder was evaluated by measuring lengths of cut-offs of a strip stock by a digimatic vernier caliper. At each predetermined feed pitch, the proposed roll feeder was tested 100 times by varying the feed/cut intervals as 2.0/1.5, 3.0/2.0, and 3.5/2.5 s as test sets. The lengths of the cutoffs of the strip stock ranged from 9.89-10.34, 12.1-12.65, and 15.21-15.67 mm at the predetermined 10, 12, and 15 mm feed pitch, respectively, among the total of 300 samples in each feed pitch, regardless of the feed/shear interval. Therefore, the feed/cut interval at each selected feed pitch was found to have no effect on the accuracy of the intermittent advancing of the strip stock.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.2
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• pp.11-18
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• 2001

To clarify the influence of SAC shape of hole-type diesel nozzle on injection characteristics and spray patterns, the injection rate of three nozzle types(standard SAC nozzle, Needle-cut VCO nozzle and VCO nozzle) were measured by Zeuch's method and pictures of the sprays were taken by CCD camera. As the pump speed became higher, the injection characteristics of the three nozzles were different. Injection rate and perssure curves at the high pressure pipe in Needle-cut VCO nozzle were much more similar to the VCO nozzle than those of the SAC nozzle. When the needle was at pre-lift period for all speeds, the spray of the Needle-cut VCO nozzle showed almost the same shape as the SAC type nozzle. There was no differense in spray pattern at the needle full-lift periods.

• Journal of Biosystems Engineering
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• v.27 no.4
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• pp.301-310
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• 2002

With a purpose to manufacture an onion peeler, the root cutting equipment of the onion could be attached to a prototype onion peeler was developed. Before the experiment, the distribution of the dimensions of the Korean native onion were measured. And some types of the blades to cut and remove the root of the onion were designed and such characteristics as feasible revolution, conveying speed, and power requirement were investigated. From the result of the test, the selected one among the various cutters was the wing type blade with the round blade to cut out the root and with the vertical blade to cut a circular line. The optimum operating conditions of the wing type blade were revealed the revolution with no load was at 630 rpm, and the conveying speed was 0.08 m/s. Under these conditions, the maximum torque was 5.25 kg·m and the power requirement was 33 W, respectively.