• Journal of the Korean Society for Precision Engineering
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• v.24 no.9
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• pp.76-85
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• 2007

An optical rotary encoder is easy to implement for automatic control applications. In particular, the output of the encoder has a digital form pulse, which is also easy to be connected to a popular digital controller. By using the encoder, there are various angular velocity detecting methods, M-, T-, and M/T-method. Each of them has a property of its own. They have common limitation that the angular velocity detection period is strongly subject to the destination velocity magnitude in case of ultimate low range. They have ultimate long detection period or cannot even detect angular velocity at near zero velocity. This paper proposes a dual encoder system with two encoders of normal resolution. The dual encoder system is able to keep detection period moderately at near zero velocity and even detects zero velocity within nominal period. It is useful for detecting velocity in case of changing rotational direction at which there occurs zero velocity. In this paper, various experimental results are shown for the dual encoder system validity.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.2
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• pp.321-323
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• 2012

Cognitive radio has been recently proposed to dynamically access unused-spectrum. Since the spectrum availability for opportunistic access is determined by spectrum sensing, sensing is identified as one of the most crucial issues of cognitive radio networks. The PHY-layer sensing, as a part of spectrum sensing in cognitive radio, concerns the sensing mechanism to determine channel to be sensed and to access. One of the important issues in the PHY-layer sensing control is to find an available sensing period and trade-off between spectrum sensing and data transmission. In this paper, we show the relationship between spectrum sensing and data transmission according to the sensing period. We analyze and propose the new scheme to evaluate optimal sensing period.

• Environmental Analysis Health and Toxicology
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• v.8 no.1_2
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• pp.11-17
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• 1993

Radioactive elements Li/sup +/, Rb/sup +/and Cs/sup +/ effect the period shortening in proportion to the higher concentration on the growth of Neurospora crassa. 1 mM LiCl presented the result of the period length 0.52 h shorter than average circadian rhythm 21.66 h. 1 mM RbCl reduced the period length 1.13 h than control period 21.89 h and 1 mM CsCl reduced 2.12 h than control period 21.89 h. In the equal concentration Cs/sup +/ had an extreme effect. Fatal doses of Li/sup +/, Rb/sup +/ and Cs/sup +/ are 20mM, 30mM and 20mM. In the fatal concentration Neurospora didn't develop more after 7 days and the formation of spores were not given in regular order. Circadian length of Neurospora decreased generally at the last cycle of the growth.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.11
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• pp.1170-1176
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• 2008

In this study, we propose a new method to control both the beat clarity and beat period in a ring structure. An equivalent ring which satisfies the measured mode condition is determined by using the equivalent ring theory. Theoretical analysis and finite element analysis on the equivalent ring are performed to investigate the effect of the local structural modification on the beat clarity and beat period. Beat clarity and period are improved by attaching asymmetric mass or decreasing local thickness. Through the analysis on the equivalent ring, the proper position and the amount of the local variation are determined to satisfy the required clarity and period condition. All the analysis results are compared and verified by the experiment.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.468-472
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• 2003

The lifting technique is a standard control procedure that is commonly applied to dual-rate systems, where a critical difficulty is that care must be taken so that the resulting equivalent system preserves the causality constraint between the control signal and the measured output. To overcome this difficulty, the most attractive result has been suggested by defining control time sequences as the union of sample and hold time sequences. However, the sacrifice of regular control period scheme results in some serious disadvantages; restrictions on the implementation to hardware and the corresponding inefficient control scheme. On the contrary, this paper proposes a novel dual-rate control technique, which redescribes the system as a control-rate-based system having regular control period and designs the controller, with no causality constraint, through Linear Matrix Inequality (LMI) formulation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.481-484
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• 2006

Pitch period detection algorithms are applied to various speech signal processing fields such as speech recognition, speaker identification, speech analysis and synthesis. Furthermore, many pitch detection algorithms of time and frequency domain have been studied until now. AMDF(average magnitude difference function) ,which is one of pitch period detection algorithms, chooses a time interval from the valley point to the valley point as the pitch period. AMDF has a fast computation capacity, but in selection of valley point to detect pitch period, complexity of the algorithm is increased. In order to apply pitch period detection algorithms to the real world, they have robust prosperities against generated noise in the subway environment etc. In this paper we proposed the modified AMDF algorithm which detects the global minimum valley point as the pitch period of speech signals and used speech signals of noisy environments as test signals.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.9
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• pp.4501-4504
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• 2012

In recent decades, decreasing trends in esophageal cancer mortality have been observed across China. We here describe esophageal cancer mortality trends in Linzhou city, a high-incidence region of esophageal cancer in China, during 1988-2010 and make a esophageal cancer mortality projection in the period 2011-2020 using a Bayesian approach. Age standardized mortality rates were estimated by direct standardization to the World population structure in 1985. A Bayesian age-period-cohort (BAPC) analysis was carried out in order to investigate the effect of the age, period and birth cohort on esophageal cancer mortality in Linzhou during 1988-2010 and to estimate future trends for the period 2011-2020. Age-adjusted rates for men and women decreased from 1988 to 2005 and changed little thereafter. Risk increased from 30 years of age until the very elderly. Period effects showed little variation in risk throughout 1988-2010. In contrast, a cohort effect showed risk decreased greatly in later cohorts. Forecasting, based on BAPC modeling, resulted in a increasing burden of mortality and a decreasing age standardized mortality rate of esophageal cancer in Linzhou city. The decrease of esophageal cancer mortality risk since the 1930 cohort could be attributable to the improvements of socialeconomic environment and lifestyle. The standardized mortality rates of esophageal cancer should decrease continually. The effect of aging on the population could explain the increase in esophageal mortality projected for 2020.

• Food Science of Animal Resources
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• v.20 no.1
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• pp.64-71
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• 2000

The volatile flavour compounds such as acetaldehyde, acetone, ethanol, diacetyl and acetoin were detected by gas chromatography in adlay yoghurt during fermentation and storage period at 4 $pm$1$^{circ}C$, but acetoin was trace. The contents of acetaldehyde of adlay yoghurt showed maximum immediately after fermentation and decreased significantly(P<0.05) with storage period and were in order of adlay yoghurt fermented with YC-380, ABT-D and ABT-4. The contents of acetone were shown similar trend to acetaldehyde and those of adlay yoghurt fermented with YC-380, ABT-4 and ABT-D, decreased rapidly from 6 days, 9 days and 12 days of storage, respectively. The contents of ethanol increased during the storage period and those were significant differences(p<0.05) between 6 days and 9 days of storage period in control and treatments. The contents of diacetyl were detected in control and treatments at 9 days of storage and increased slightly during the storage period. The contents of volatile flavour compounds of T1 showed similar to that of control and slightly high compared to those of treatments, and decreased gradually with increasing the level of addition of adlay in treatments. The taste, flavour and texture of T1 immediately after fermentation and during the storage period at 4$\pm$1$^{\circ}C$ were slightly higher than those of control and treatments. The scores of sensory evaluation of treatments except T1 were lowered significantly(p<0.05) with increasing level of addition of adlay. Adlay yoghurt fermented with YC-380 and ABT-4 and ABT-D were superior to both of taste and flavour, and texture, respectively. From the results mentioned above, the addition of taste and flavour, and texture, respectively. From the results mentioned above, the addition of adlay at 1% (w/v) level in skim milk substrate were suitable for quality of adlay yoghurt such as volatile flavour compounds and sensory property.

• Journal of the Korean Society of Physical Medicine
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• v.2 no.2
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• pp.101-112
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• 2007

Purpose : The purpose of this study was to evaluate influence of sacroiliac joint mobilization on lower extremity muscle strength. Methods : The subjects were consisted of thirty patients who had Leg length inequality(LLI) of more than 10mm(16 females. 14 males) from 21 to 41 years of age(mean aged 24.87). All subjects randomly assigned to sacroiliac joint mobilization group(n=15), control group(n=15). sacroiliac joint mobilization group received sacroiliac joint mobilization about 10 minutes for 3 times per week during 4 weeks period. Control group not received intervention during 4 weeks period. The tape measure method(TMM) was used to measure functional Leg length inequality. Biodex System 3 Pro was used to measure strength of Knee extension & flexion. All measurements of each subjects were measured at pre-test, 2weeks post-test and 4weeks post-test. Results : 1. The LLI of sacroiliac joint mobilization group was significantly reduced according to within treatment period(p<.05), most significantly reduced between pre-test and post-test(p<.05). sacroiliac joint mobilization group significantly more reduced than control group(p<.05). 2. The knee extension strength of sacroiliac joint mobilization group was significantly increased according to within treatment period(p<.05), most significantly increased between pre-test and post-test(p<.05). sacroiliac joint mobilization group significantly more increased than control group(p<.05). 3. The knee flexion strength of sacroiliac joint mobilization group was significantly increased according to within treatment period(p<.05), most significantly increased between pre-test and post-test(p<.05). sacroiliac joint mobilization group significantly more increased than control group(p<.05). Conclusion : sacroiliac joint mobilization can reduce LLI and increased lower extremity muscle strength.

• Journal of the Korean Society of Physical Medicine
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• v.2 no.2
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• pp.183-194
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• 2007

Purpose : The purpose of this study was to evaluate influence of therapeutic exercise on functional leg length inequality(LLI). Methods : The subjects were consisted of thirty patients who had Leg length inequality(LLI) of more than 10mm(l6 females. 14 males) from 20 to 35 years of age(mean aged 24.23). All subjects randomly assigned to contract-relax exercise of proprioceptive neuromuscular facilitation(PNF) group(n=15), control group(n=15). Contract-relax exercise group received contract-relax exercise about 10 minutes with therapeutic massage about 15 minutes for 3 times per week during 4 weeks period. Control group not received intervention during 4 weeks period. The tape measure method(TMM) was used to measure functional Leg length inequality. Biodex System 3 Pro was used to measure strength of Knee extension & flexion. All measurements of each subjects were measured at pre-test, 2weeks post-test and 4weeks post-test. Results : 1. The LLI of contract-relax exercise group was significantly reduced according to within treatment period(p<.05), most significantly reduced between pre-test and post-test(p<.05). Contract-relax exercise group significantly more reduced than control group(p<.05). 2. The knee extension strength of contract-relax exercise group was significantly increased according to within treatment period(p<.05), most significantly increased between pre-test and post-test(p<.05). Contract-relax exercise group significantly more increased than control group(p<.05). 3. The knee flexion strength of contract-relax exercise group was significantly increased according to within treatment period(p<.05), most significantly increased between pre-test and post-test(p<.05). Contract-relax exercise group significantly more increased than control group(p<.05). Conclusion : Contract-relax exercise applied with therapeutic massage can reduce LLI and increased lower extremity muscle strength.