• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.1485-1488
• /
• 2003

This paper proposes a wireless EMG-based human-computer interface (HCI) for persons with disabilities. For the HCI, four interaction commands are defined by combining three elevation motions of shoulders such as left, right and both elevations. The motions are recognized by comparing EMG signals on the Levator scapulae muscles with double thresholds. A real-time EMG processing hardware is implemented for acquiring EMG signals and recognizing the motions. To achieve real-time processing, filters such as high- and low-pass filter and band-pass and -rejection filter, and a full rectifier and a mean absolute value circuit are embedded on a board with a high speed microprocessor. The recognized results are transferred to a wireless client system such as a mobile robot via a Bluetooth module. From experimental results using the implemented real-time EMG processing hardware, the proposed wireless EMG-based HCI is feasible for the disabled.

• Journal of the Optical Society of Korea
• /
• v.15 no.3
• /
• pp.310-317
• /
• 2011

Perceptibility and acceptability are the most often used threshold units in the field of color science. The former refers to a just perceptible difference and the latter evokes a tolerable color difference. Such thresholds can be very significant to color quality control processes in the printing industry and should be defined in quality measure units. Optical density (OD) and color difference models are usually utilized as color quality measures and have been provided in a considerable number of commercial measuring devices such as spectrophotometers. However, their merits and traits are far less understood in the literature. The present study intends to evaluate performance of those color quality measures including the OD and widely known color difference models, e.g. ${\Delta}E{^*}_{ab}$, ${\Delta}E_{CMC(l:c)}$ and ${\Delta}E{^*}_{00}$. A set of psychophysical assessments were carried out in order to accumulate the perceptibility and acceptability thresholds data, and their central trend was compared with the color quality measure estimates.

• International Journal of Contents
• /
• v.8 no.2
• /
• pp.19-22
• /
• 2012

New and handoff calls control mechanisms are the key point to wireless cellular networks. In this paper, we present an adaptive algorithm for dynamic channel allocation scheme with guard channels and also with handoff calls waiting queue ensuring that handoff calls take priority over new calls. Our goal is to find better tradeoff between handoffs and new calls blocking probabilities in order to achieve more efficient channel utilization. Simpy is a Python based discrete event simulation system. We use Simpy to build our simulation models to get analytical data.

• Korean journal of applied entomology
• /
• v.31 no.3
• /
• pp.205-240
• /
• 1992

In reality, it is a green revolution of the entire agricultural matrix in Korea that integrated pest control plays an important role in the possible breakthrough in rice self-sufficiency. In paddy agroecosystem as man-modified environment, rice is newly established every year by transplantation under diverse water regimes which affect a microclimate. Standing water benefits rice by regulating the microclimate, but it favors the multiplication of certain pets through the amelioration of the microclimate. Further, the introduction of high yielding varieties with the changing of cultural practices results in changing occurrence pattern of certain pests. In general, japonica type varieties lack genes resistant to most of the important pests and insect-borne virus diseases, whereas indica type possesses more genes conferring varietal resistance. Thus, this differences among indica type, form the background of different approaches to pest management. The changes in rice cultivation such as double cropping, growing high-yielding varieties requiring heavy fertilization, earlier transplanting, intensvie-spacing transplanting, and intensive pesticide use as a consequence of the adoption of improves rice production technology, have intensified the pest problems rather than reduced them. The cultivation of resistant varieties are highly effective to the pest, their long term stability is threathened because of the development of new biotypes which can detroy these varieties. So far, three biotypes of N. lugens are reported in Korea. Since each resistant variety is expected to maintain several years the sequential release of another new variety with a different gene at intervals is practised as a gene rotation program. Another approach, breeding multilines that have more than two genes for resistance in a variety are successfully demonstrated. The average annual rice losses during the last 15 years of 1977-’91 are 9.3% due to insect pests without chemical control undertaken, wehreas there is a average 2.4% despite farmers’insecticide application at the same period. In other words, the average annual losses are prvented by 6.9% when chemical control is properly employed. However, the continuous use of a same group of insecticides is followed by the development of pest resistance. Resistant development of C. suppressalis, L. striatellus and N. cincticeps is observed to organophosphorous insecticides by the mid-1960s, and to carbamates by the early 1970s in various parts of the country. Thus, it is apparent that a scheduled chemical control for rice production systems becomes uneconomical and that a reduction in energy input without impairing the rice yield, is necessarily improved through the implementation of integrated pest management systems. Nationwide pest forecasting system conducted by the government organization is a unique network of investigation for purpose of making pest control timely in terms of economic thresholds. A wise plant protection is expected to establish pest management systems in appropriate integration of resistant varieties, biological agents, cultural practices and other measures in harmony with minimizing use of chemical applications as a last weapon relying on economic thresholds.

• The Korean Journal of Pain
• /
• v.14 no.1
• /
• pp.7-11
• /
• 2001

Background: Although several mechanisms of causalgia, which results from a partial injury to the peripheral nerve trunk, have been proposed, whether or not antidromic impulses from the injured neurons contribute to the development of the mechanical hyperalgesia has not been studied. The purpose of this experiment is was to investigate the role of antidromic impulses to the peripheral sensory receptor site on the development of mechanical hyperalgesia in a rat model of peripheral neuropathy. Methods: Rats were prepared with tight ligation of by tightly ligating the left fifth and sixth lumbar spinal nerves. The effect of bupivacaine pretreatment on the development of mechanical hyperalgesia was evaluated by injecting 0.5% bupivacaine (0.3 ml) into the plantar surface of the left hind paw before the skin incision was made. For the control group, normal saline (0.3 ml) was injected instead of bupivacaine. To measure the mechanical hyperalgesia, paw withdrawal thresholds were measured using a series of von Frey hairs. Mechanical hyperalgesia was measured a the day before, and 1, 2, 3, 4, 7, and 14 days after the surgery. Results: The control group showed decreased withdrawal thresholds from the day after the surgery (the values were $14.0{\pm}0.5$, $8.9{\pm}1.3$, $8.4{\pm}1.6$, $6.9{\pm}1.2$, $8.8{\pm}1.5$, $10.5{\pm}1.3$, and $8.6{\pm}1.3$ g; at -1, 1, 2, 3, 4, 7, and 14 days after the surgery, respectively). However, withdrawal thresholds of the bupivacaine-pretreated group showed increased withdrawal thresholds for three days after the surgery ($14.5{\pm}0.3$, $12.6{\pm}1.4$, $12.7{\pm}1.1$, $10.5{\pm}1.3$ g; at 1, 1, 2, 3 days after the surgery). Conclusions: Our result suggests that antidromic impulses to the peripheral sensory receptors are at least partly responsible for the initial development of mechanical hyperalgesia in a rat model of peripheral neuropathy.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.3A
• /
• pp.129-139
• /
• 2003

CAC is a very important issue in CDMA system in order to protect the required QoS(quality of service) and increase the system's capacity. In this paper, we proposed and analyzed a call admission control scheme using multiple thresholds, which can provide quick processing time and better performance. There are two effective thresholds used to decide call admission. One is the number of active users, and the other is the signal to interference ratio(SIR). If the threshold of active users are lower than the low number of users threshold, we accept the new call without any other conditions. Otherwise, we check the current SIR to guarantee the quality of our service. System then accepts the new call when the SIR satisfies system requirement. Otherwise, the call will be rejected. Multiple threshold schemes are investigated and their performance is compared with the number of user and power based CAC's. simulation results are provided to evaluate the performance.

• Journal of Mechanical Science and Technology
• /
• v.19 no.4
• /
• pp.985-992
• /
• 2005

Vehicle Stability Control (VSC) system prevents vehicle from spinning or drifting out mainly by braking intervention. Although a control threshold of conventional VSC is designed by vehicle characteristics and centered on average drivers, it can be a redundancy to expert drivers in critical driving conditions. In this study, a manual adaptation of VSC is investigated by changing the control threshold. A control threshold can be determined by phase plane analysis of side slip angle and angular velocity which is established with various vehicle speeds and steering angles. Since vehicle side slip angle is impossible to be obtained by commercially available sensors, a side slip angle is designed and evaluated with test results. By using the estimated value, phase plane analysis is applied to determine control threshold. To evaluate an effect of control threshold, we applied a 23-DOF vehicle nonlinear model with a vehicle planar motion model based sliding controller. Controller gains are tuned as the control threshold changed. A VSC with various control thresholds makes VSC more flexible with respect to individual driver characteristics.

• Korean journal of applied entomology
• /
• v.48 no.1
• /
• pp.81-86
• /
• 2009

Economic injury level and control thresholds for the management of beet army worm, Spodoptera exigua (Lepidoptera: Noctuidae) were evaluated on chinese cabbage of two different planting time. Two inoculation times were tested for each planting and the number of inoculated larva was 10, 20, 40, 80, respectively. Damages of leaves by first inoculation were 63.2% after eight days planting on 80 larva inoculation plot. By the second inoculation, those were below 50% after 20 days planting on the end of September. The linear relationships between population density and yield reduction were as following; Y = -10.62x + 867.9 ($R^2\;=\;0.643$) for 5 days and Y=-6.432x + 1074 ($R^2\;=\;0.720$) for 20 days. Based on these results the economic injury level was 5.4 larva for five days and 9.0 larva for 20 days per 20 chinese cabbage. The control thresholds calculated by 80% level of economic injury level were 4.3 and 7.2 larva, respectively.

• Korean journal of applied entomology
• /
• v.45 no.3 s.144
• /
• pp.317-325
• /
• 2006

According to the preceding survey on insect pests of the green perilla, Perilla frutescens var. japonica HARA, The major pests were Aphis egomae Shinji, Pyrausta panopealis (Walker), Tetranychus urticae Koch, Polyphagotarsonemus lotus Banks, Tetranychus kanzawai Kishida at Guemsan, Chungnam, 2004. Aphis egomae causes nearly 100% injury of the green perilla in uncontrolled green houses. A field study was conducted to estimate economic injury levels (EILs) and control thresholds (CTs) for A. egomae injuring green perilla in green houses. Different densities of A. egomae ranged from 1 to 80 aphids per 100 plants in early inoculation. The mean injurying rate of plant was 2.4% to 40.5% at the end of June at differently inoculated levels. The economic loss time calculated by the ratio of cost managing aphid to market price (C/V) (C: cost managing aphid, V: Market price) in early season (from May to 13. June) was 5.8% and in peak season (from 13. June to 30. June) was 9.3%. Economic injury level in early and peak season was 5.3 aphids per plant and economic injury levels in peak season were 0.6 aphids per plant and 7.6% injured rate of plant. The control thresholds calculated by 80% level of economic injury level in peak season were 0.5aphids per plant and 6.1% injury rate of plant, respectively.

• Korean journal of applied entomology
• /
• v.46 no.3
• /
• pp.431-435
• /
• 2007

Control thresholds for the management of beet army worm, Spodoptera exigua (Lepidoptera : Noctuidae) were evaluated on welsh onion of two different planting time. Two inoculation times were tested for each planting and the number of inoculated larva was 5, 10, 20, 40 per twenty plants. The injured rate of leaves was 33.5% to 10.9% at 7th September at 40 to 5 larva inoculation plot on the five days planting. That of leaves was 20.5% at 40 larva on the twenty days planting. The yields of welsh onion on non-inoculation plot were 4,395 kg per 10a. The rate of reduced yields was 49.2%(1,774.2 kg) and 36.5%(2,220.5 kg) at 40 larva inoculation on the 5 and 20 days planting, respectively. The linear relationships between population density and yield reduction were as following; it was Y=-43.474X + 3419.6 ($R^2\;=\;0.9698$) for 5 days and Y=-32.977X + 3518.9 ($R^2\;=\;0.9928$) for 20 days. Based on these results the control threshold level was estimated to be 1.8 larva for 5 days and 4.6 larva for 20 days per 20 plant. The more damaged leaves by S. exigua larva, the more yield reduction on welsh onion.