• Journal of Sensor Science and Technology
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• v.5 no.4
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• pp.47-56
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• 1996

The basic principle and characteristics of a DTG(dynamically tuned gyroscope) are presented in this paper, which is used for the detection of disturbance and for the stabilization of gimbal. An accurate model of the rate mode DTG is proposed. This model has a resonance characteristics which is more similar to the characteristics of practical systems than the conventional 2nd order system model. Therefore, this model is applicable to the general rate mode gyroscope. Some problems at using DTG for a real electro optical tracking system are discussed and a solution is described.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.930-937
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• 1994

Straodown intertial navigation system(SDINS) is a navigational instrument necessary to guide and control a free vehicle. Dynamically Tuned Gyroscope(DTG) which is widely applied to SDINS convers a wide dynamic range and is simple and small. In study, the analysis of mechanical parts or sensor parts and research of balancing is performed for manufacturing a DTG. In error analysis the criterion considered during designing and manufacturing is established by quantitatively anayzing the effect of DTG performance by tolerance. And the theory of dynamic balancing is derived and unbalance is reduced through experiment. And the stiffness of flexure is verified by tuning experiment.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1146-1148
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• 1996

In this paper, uncertain parameters of the heat transfer model of a Dynamically Tuned Gyroscope (DTG) are estimated by the Recursive Least Squares (RLS) method. Also, using this model, a temperature controller for a DTG is designed. As the temperature controller, a PI controller is used. It is presented that a controller can be easily designed when the heat transfer model of a DTG is used. By simulations and experiments, it is shown that the estimated heat transfer model is appropriate and the desired performance of the temperature controller is satisfied.

• Journal of the Korean Society of Physical Medicine
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• v.15 no.2
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• pp.23-30
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• 2020

PURPOSE: The purpose of this study was to examine the effects of dual-task training with cognitive tasks on cognitive functions and β-amyloid levels in the elderly with mild dementia. METHODS: The subjects were 36 elderly inpatients diagnosed with mild dementia at S Hospital located in Gyeongsangbuk-do, South Korea. The patients were randomly divided into a dual-task training group (DTG; n = 18) or a single-task training group (STG; n = 18). DTG performed dual-task training with cognitive tasks while STG performed only exercise tasks. These groups performed their respective exercises during a 30-minute session occurring three times a week over an 8-week period. MMSE-K and GDS were used to measure the subjects' cognitive function. To assess the subjects' dementia-related factors, their β-amyloid levels were measured by blood analysis. RESULTS: The results of the experiment were as follows: DTG showed statistically significant differences between their MMSE-K scores and β-amyloid levels before and after training (p < .05), whereas they exhibited no statistically significant differences in their GDS scores. MMSE-K scores and β-amyloid levels were significantly different between DTG and STG after training. CONCLUSION: The present study's overall results indicate that dual-task training with cognitive tasks is more effective than single-task training in improving cognitive functions and β-amyloid levels in the elderly with mild dementia. In other words, regular dual-task training can be considered as effective in improving cognitive function and dementia-related factors in the elderly with mild dementia and thus may be suggested as an effective exercise method for the treatment and early prevention of dementia.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.2
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• pp.87-97
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• 2018

Bus, a major transportation mode, doesn't have a systematical evaluation system for dangerous driving behavior yet. This paper analyzes the characteristics and pattern of bus driving behavior using Digital Tacho Graph(DTG) data on express bus. 8 types of dangerous driving behavior were considered according to timeslot, the day of week and weather condition. As results, rapid acceleration, rapid left right turn and rapid deceleratio accounted for more than 97% and relatively high percentages were shown in dawn, on Friday and on the clear day, respectively. From the statistical analysis, correlation between the dangerous driving types and difference according the timeslot were found, and 3 groups considering the level of the dangerous driving were suggested. This study contributes to setting an efficient and reliable eduction system for using driving simulators.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.519-521
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• 1987

Among the gyroscopes used for SDINS, the dynamically turned gyroscope (DTG) covers a wide dynamic range while it is simple and small. In addition, it is a two-degree-of freedom gyro; it can detect two-axis input simultaneously. DTG, since its development in 1970's, is widely accepted for strapdown inertial systems. In the first year, we have concentrated on developing a two degree-of-freedom DIG. An interdisciplinary research team has been formed to accomplish the first year objective. Five departments in the College of Engineering, Seoul National University are involved. They are; 1) Department of Control and Instrumentation, 2) Department of Mechanical Design and Production, 3) Department of Electrical Engineering, 4) Department of Electronic Engineering, and 5) Department of Metallurgical Engineering. In addition, the Department of Precision Mechanical Engineering of Pusan National University is subcontracted to develop a test procedure for gyroscope and SDINS. Gyroscope is a key sensor for SDINS. Furthermore gyroscope itself is used as a. independent sensor for vehicle guidance and control and fire control system. Gyroscope and SDINS are an important for defense, aeronautical, and space industries that Korea is and will be actively involved. Upon the success of the project, they are expected to be manufactured in Korea under a cooperative effort between university and industry.

• Structural Engineering and Mechanics
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• v.82 no.1
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• pp.69-79
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• 2022

This paper discusses the field testing of two single-span double-tee girder (DTG) bridges in South Dakota to determine live load distribution factors (LLDFs) and the dynamic load allowance (IM). One bridge had seven girders and another had eight girders. The longitudinal girder-to-girder joints of both bridges were deteriorated in a way that water could penetrate and the joint steel members were corroded. A truck traveled across each of the two bridges at five transverse paths. The paths were tested twice with a crawl speed load test and twice with a dynamic load. The LLDFs and IM were determined using strain data measured during the field tests. These results were compared with those determined according to the AASHTO Standard and the AASHTO LRFD specifications. Nearly all the measured LLDFs were below the AASHTO LRFD design LLDFs, with the exception of two instances: 1) An exterior DTG on the seven-girder bridge and 2) An interior DTG on the eight-girder bridge. The LLDFs specified in the AASHTO Standard were conservative compared with the measured LLDFs. It was also found that both AASHTO LRFD and AASHTO Standard specifications were conservative when estimating IM, compared to the field test results for both bridges.

• Journal of the Korean Recycled Construction Resources Institute
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• v.12 no.1
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• pp.8-16
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• 2024

Limestone (CaCO₃, calcium carbonate), which is used as a raw material in the portland cement and steel industry, emits CO₂ through decarbonation by high temperatures in the manufacturing process. To reduce CO₂ emissions by the use of raw materials like limestone, it has been proposed to replace limestone with various industrial by-products that contain CaO but less or none of the carbonated minerals, that cause CO₂ emissions. Loss of Ignition (LOI), Thermogravimetric analysis (TG), and Infrared Spectroscopy (IR) are used to quantitative the amount of CO₂ emission by using these industrial by-products, but CO₂ emissions can be either over or underestimated depending on the characteristics of by-product materials. In this study, we estimated CO₂ contents by LOI, TG, IR and DTG(Differential Thermogravimetric analysis) of calcite(CaCO₃) and samples that contain CO₂ in the form of carbonate and whose weight increases by oxidation at high temperatures. The test results showed for CaCO₃ samples, all test methods have a sufficient level of reliability. On the other hand, for the CO₂ content of the sample whose weight increases at high temperature, LOI and TG did not properly estimate the CO₂ content of the sample, and IR tended to overestimate compared to the predicted value, but the estimated result by DTG was close to the predicted valu e. From these resu lts, in the case of samples that contain less than a few percent of CO₂ and whose weight increases during the temperature that carbonate minerals decompose, estimating the CO₂ content using DTG is a more reasonable way than LOI, TG, and IR.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05b
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• pp.27-30
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• 2003

In this paper, the new dual trench gate Emitter Switched Thyristor (DTG-EST) is proposed for improving snap-back effect which leads to a lot of serious problems of device applications. And the parasitic thyristor that is inherent in the conventional EST is completely eliminated in this structure, allowing higher maximum controllable current densities for ESTs. The conventional EST exhibits snap-back with the anode voltage and current density 2.73V and $35A/cm^2$, respectively. But the proposed DTG-EST exhibits snap-back with the anode voltage and current density 0.96V and $100A/cm^2$, respectively.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.2
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• pp.119-126
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• 1989

In this paper, a new technique, which uses an "input compensator", is proposed to design a controller for the rebalance loop of a Dynamically Tuned Gyroscope (DTG) and the performance of this new controller is compared with that of a Proportional and Integral (PI) controller through simulation. The rebalance loop is an essential part of a DTG` it is composed of a controller, low-pass filters, notch filters and torque drivers. Among them, the controller is the main attributor to determine the performance of the rebalance loop. Through simulation, it is concluded that the performance of the newly designed controller is better than that of a PI controller in the point of (1) low maximum overshoot, (2) short settling time and (3) small steady state error.