• IE interfaces
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• v.8 no.2
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• pp.161-169
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• 1995

In this paper, a threshold policy is considered for the Markovian queueing system with server vacations. The threshold policy considered in this paper has the following form: "when the number of customers present in the system increases to N, the server is turned on and serves customers until the system becomes empty". In this paper, we show how the finite capacity or finite population queueing system under a threshold policy can be modeled by the stochastic Petri net. The performance evaluation of the model is carried out using the software called "SPNP". Some examples are also presented in which it is shown that how the optimal threshold policies can be obtained under a linear cost structure.

• Bulletin of the Korean Chemical Society
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• v.12 no.5
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• pp.529-536
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• 1991

In this paper, the question whether the curvature of the minimum energy path can affect the dynamic threshold was tested using the boundary trajectory method developed by Chesnavich and coworkers. For nonreactive system, the MO EXP model potential surface was used with modified equilibrium distance to control the curvature. The results showed that there is no relation between the curvature and the dynamic threshold. In order to study the reactive system, a generalization of the boundary trajectory method was achieved to apply on the nonsymmetric system. We have found no correspondence between the curvature and the dynamic threshold of the system. It was also shown that the fate of the trajectories strongly depends on the shape of potential surface around the turning points along the symmetric stretch line.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.8
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• pp.116-121
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• 2001

The paper presents the dynamic characteristics of a rotor-bearing system supported by an actively controlled hydrodynamic journal bearing. The proportional. derivative and integral controls are adopted for the control algorithm to control the hydrodynamic journal bearing with an axial groove. Also, the cavitation algorithm implementing the Jakobsson-Floberg-Olsson boundary condition is adopted to predict cavitation regions in the fluid film more accurately than conventional analysis, which uses the Reynolds condition. The speed at onset of instability of a rotor-bearing system is increased by both proportional and derivative control of the bearing. The proportional control increases the stability threshold without affecting the whirl ratio. However, for the derivative control of the bearing, increase of stability threshold speed is accompanied by a parallel reduction of the whirl ratio. The integral control has no effect on stability characteristics of hydrodynamic journal bearing. The PD-control is more effective than proportional or derivative control. Results 7how the active control of bearing can be adopted for the stability improvement of a rotor-bearing system.

• JSTS:Journal of Semiconductor Technology and Science
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• v.10 no.3
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• pp.240-250
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• 2010

Double Gate MOSFETs (DG MOSFETs) with doping in one or two thin layers of an otherwise intrinsic channel are simulated to obtain the transport characteristics, threshold voltage and leakage current. Two different device structures- one with doping on two layers near the top and bottom oxide layers and another with doping on a single layer at the centre- are simulated and the variation of device parameters with a change in doping concentration and doping layer thickness is studied. It is observed that an n-doped layer in the channel reduces the threshold voltage and increases the drive current, when compared with a device of undoped channel. The reduction in the threshold voltage and increase in the drain current are found to increase with the thickness and the level of doping of the layer. The leakage current is larger than that of an undoped channel, but less than that of a uniformly doped channel. For a channel with p-doped layer, the threshold voltage increases with the level of doping and the thickness of the layer, accompanied with a reduction in drain current. The devices with doped middle layers and doped gate layers show almost identical behavior, apart from the slight difference in the drive current. The doping level and the thickness of the layers can be used as a tool to adjust the threshold voltage of the device indicating the possibility of easy fabrication of ICs having FETs of different threshold voltages, and the rest of the channel, being intrinsic having high mobility, serves to maintain high drive current in comparison with a fully doped channel.

• Journal of Korea Water Resources Association
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• v.47 no.5
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• pp.491-500
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• 2014

To estimate the severity of streamflow drought, this study introduced the concept of streamflow drought index based on threshold level method and Seomjingang Dam inflow was applied. Threshold levels used in this study are fixed, monthly and daily threshold, The $1^{st}{\sim}3^{rd}$ analysis results of annual drought, the severe hydrological droughts were occurred in 1984, 1988 and 1995 and the drought lasted for a long time. Annual compared to extreme values of total water deficit and duration, the drought occurred in 1984, 1988, 1995 and 2001 was serious level. In the results of study, because a fixed threshold level is not reflect seasonal variability, at least the threshold under seasonal level was required. Threshold levels determined by the monthly and daily were appropriate. The proposed methodology in this study can be used to forecast low-flow and determine reservoirs capacity.

• Korean Journal of Psychosomatic Medicine
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• v.6 no.1
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• pp.22-27
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• 1998

Thirteen female patients of somatization disorder, undifferentiated somatoform disorder and somatoform disorder, NOS, diagnosed by DSM-IV were studied for their pain threshold and serum testosterone and the results were compared with the respective data of 20 control females. The results are as follows : 1) The pain threshold as measured by Variable Weight Pressure Algometer was significantly lower in the patient group(153.8${\pm}$39.5 gm/$0.05mm^2$) as compared to the control group(197.5${\pm}$66.7 gm/$0.05mm^2$)(p<0.05). 2) There was no significant difference of serum testosterone between the patient(0.175${\pm}$0.081 ng/ml) and the control(0.174${\pm}$0.108 ng/ml) groups. 3) A significant positive correlation was noted between the pain threshold and serum testosterone in the patient group(r=0.632, p<0.05, two tailed, Pearson's correlation test), but not in the normal control group(r= -0.405). From these results, it was suggested that the role of testosterone in endogenous pain control system might be more important in somatoform disorders than normals.

• Journal of Korean Physical Therapy Science
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• v.27 no.3
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• pp.1-11
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• 2020

Background: The purpose of this study was to investigated the effects of threshold resistance inspiratory muscle training on respiratory function in chronic stroke patients. Design: Randomized Controlled Trial Methods: Eighteen patient with stroke were randomly assigned to the experimental group (n=9) and control group (n=9) all testing and training. The experimental group underwent threshold resistance inspiratory muscle training with resistance adjusted of maximal inspiratory pressure, 60 breathing a day and general physical therapy 30 minutes a day, 5 times a week for 4 weeks. The control group was taken general respiratory muscle training and general physical therapy for 4 weeks in the same way. Respiratory function, walking ability were evaluated before and after the intervention. Statistical significance of the results were evaluated by ANCOVA between control group and experimental group after intervention. Results: There was a significant increase in FVC and FEV1 in the experimental group in pulmonary function tests (p<0.05). There was a significant difference with the maximum inspiratory pressure and the maximum inspiratory flow rate between experimental and control group (p<0.05). There was no significant difference with the maximum inspiratory capacity between experimental and control group (p>0.05) but the maximum inspiratory capacity of experimental group some increased than that of control group. Conclusion: These finding gave some indications that the threshold resistance inspiratory training may benefit on pulmonary function in people with stroke, and it is feasible to be included in rehabilitation interventions with this population.

• Journal of Acupuncture Research
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• v.29 no.4
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• pp.25-34
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• 2012

Objectives : This study was conducted to investigate the effects of fixed-intensity and varied-intensity electroacupuncture in pain and sensory threshold concerning parameters visual analogue scale(VAS), brief pain inventory(BPI) and quantitative sensory testing(QST), among chronic tension headache patients. Methods : Thirty patients with chronic tension headache were randomly assigned to three groups and received different kinds of electroacupuncture at $ST_{36}$ and $ST_{37}$. Group A received fixed-intensity electroacupuncture(fixed-EA), group B received varied-intensity electroacupuncture (varied-EA), and group C received only acupuncture treatment without electrical stimulation as a control group. The intervention was given three times per week, and continued in two weeks. All the experiments were conducted blindly. Results : Fixed-EA group showed a significant decrease of VAS and BPI compared to the baseline measurement, while both varied-EA and control group did not. Of the parameters of QST, subtraction of heat pain threshold(HPT) and cold pain threshold(CPT) slightly increased in all groups, but this was not significant. Conclusions : These results suggest that fixed-EA reduce pain and improve quality of life in patients with chronic tension headache and that acupuncture may regulate patient's pain sensitivity through changing sensory threshold.

• Journal of Digital Contents Society
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• v.15 no.3
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• pp.319-326
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• 2014

IEEE 802.11 WLAN uses CSMA/CA(Carrier Sense Multiple Access/Collision Avoidance) method in MAC(Media Access Control) protocol, and through the carrier sense checks whether other users use the channel during the data transmission to avoid the data collision. Currently, IEEE 802.11 standard recommends the use of a fixed threshold which gives an impact on carrier sensing range. However, the existing scheme using the fixed threshold causes the operation of network to be inefficiency owing to the mobility in MANET(Mobile Ad hoc NETwork). In this paper, we found the better network throughput to be obtained by applying the proposed scheme, which chooses properly the carrier sensing threshold and transmission rate considering SINR(Signal to Interference-plus-Noise Ratio), to the MANET.

• International Journal of Industrial Entomology and Biomaterials
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• v.4 no.2
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• pp.133-136
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• 2002

Whitefly, Dialeuropora decempuncta (Quaintance rind Baker) (Homoptera: Aleyrodidae) has attained the major pest status in mulberry, causing 24% crop loss by sucking the leaf juice and manifesting leaf curl, chlorosis and sooty mould desease during monsoon season in West Bengal, India. The assessment of economic threshold revel is an essential component for formulating the management practices. Experiments were carried out by inoculating five different densities of whitefly viz.,10, 20, 30, 40 and 50 adults on covered mulberry plants in glass houses. From the findings, it was observed that irrespective of released density, no crop loss was observed in the initial period. But with the passing of days, the percent crop loss was increased rapidly. The linear relationship between percent crop loss and number of adults released was established to highlight the significance of economic threshold. The statistical analysis in the linear form of equation showed that initial population of 10, 20, 30, 40 and 50 whiteflies/plant causes 3%, 12%, 21%, 30% and 40% crop loss in a period of 28 days which is equivalent to 57 kg, 247 kg, 437 kg, 626 kg and 816 kg leaf/acre. Execution of management practices (spray of 0.01% monocrotophos) are economical to the farmer whenever the loss is above 247 kg/acre, but below which application of control measures is not economical. From this study, it can be inferred that the economic threshold level far whitefly is 20 individuals/plant beyond which a farmer has to take appropriate control measures.