• Proceedings of the IEEK Conference
• /
• 1998.10a
• /
• pp.1227-1230
• /
• 1998

Phase control methods are used to expand the sound image in general AV system. However, these methods are effective only to the signal under 1kHz, and the listener must be located in front center of the speaker system. In this paper, we realize the realtime processing system in which phase shifting method is dominant at low frequency and precedence effect is dominant at high frequency. Two sound cards are used to process the audio signal in realtime with 16 bits stereo channel of 44.1 kHz sampling frequency. And the analog circuit is designed to process the phase shifting. In experiments the usefulness of the proposed stereo system is confirmed.

• Ocean and Polar Research
• /
• v.38 no.4
• /
• pp.339-345
• /
• 2016

Stable water vapor isotopes have been utilized as a tracer for studying atmospheric global circulations, climate change and paleoclimate with ice cores. Recently, since laser spectroscopy has been available, water vapor isotopes can be measured more precisely and continuously. Studies of water vapor isotopes have been conducted over the world, but it is the early stage in south Korea. For vapor isotopes study, a cryogenic sampling device for water vapor isotopes has been developed. The cryogenic sampling device consists of the dewar bottle, filled with extremely low temperature material and impinger connected with a vacuum pump. Impinger stays put in the dewar bottle to change the water vapor which passes through the inside of impinger into the solid phase as ice. The fact that water vapor has not sampled completely leads to isotopic fractionation in the impinger. To minimize the isotopic fractionation during sampling water vapor, we have tested the method using a serial connection with two sets of impinger device in the laboratory. We trapped 98.02% of water vapor in the first trap and the isotopic difference of the trapped water vapor between two impinger were about 20‰ and 6‰ for hydrogen and oxygen, respectively. Considering the amount of water vapor trapped in each impinger, the isotopic differences for hydrogen and oxygen were 0.33‰ and 0.06‰, respectively, which is significantly smaller than the precision of isotopic measurements. This work can conclude that there is no significant fractionation during water vapor trapping.

• Journal of Biomedical Engineering Research
• /
• v.11 no.1
• /
• pp.147-156
• /
• 1990

A two-dimensional pulsed doppler system for ultrasonic blood velocity doppler signals is studied and implemented. The second-order sampling method and serial data processing procedures are utillized in the sys- tem, which eliminates the untuning problems at phase channels in the quadrature detection method as well as in the channels of parallel data processing. rho digital signal processor used in this system allows a hardware savings and flexible design options. The efficiency of the various mean frequency estimators in the second-order sampling system is examined by computer simulation as a function of the intersequence sample delay time. The temporal delay for the quadrature component is changed from $1/(4f_o){\;}to{\;}3/(4f_o){\;}and{\;}5/(4f_o)$ where to is the center frequency of the transducer, It is found that autocorrelator is the optimum frequency estimator for the second-order sampling: with !he intersequence sample delay of $1/(4f_o){\;}to{\;}3/(4f_o){\;}and{\;}5/(4f_o)$. The qualitative variation and information proportional to blood velocity in the vessel system are obtained in the VIVO experiments.

• Korean Journal of Occupational Health Nursing
• /
• v.29 no.4
• /
• pp.354-362
• /
• 2020

Purpose: This study aimed to define and clarify learning transfer in nursing. Methods: This study used a hybrid model to analyze the concept of learning transfer in nursing through three phases. For the theoretical phase, learning transfer attributes were identified through a scoping literature review. In the fieldwork phase, in-depth focus group interviews were conducted to develop attributes. Purposive sampling was performed with ten participants(five nursing students, two nurses, three nursing faculty members). In the analysis phase, the attributes and final analysis of learning transfer in nursing were extracted and integrated from the previous two phases. Results: According to the analysis, learning transfer was represented in two dimensions with eight attributes. The development of competency dimension had three attributes: 1) theory acquisition, nursing skills, professional attitude, 2) integration, and 3) analysis competency. The competency change dimension had five attributes: 1) appropriateness in patient care, 2) proficiency in patient care, 3) satisfaction, 4) achievement, and 5) confidence. Conclusion: The concept analysis might provide a basic understanding of learning transfer, a development framework toward a measurement of nursing learning transfer and effective educational nursing strategies.

• Korean Management Science Review
• /
• v.26 no.3
• /
• pp.101-115
• /
• 2009

In this paper, we propose a technology mining framework for mobile communication industry. We develop a two phase approach of new technology identification and service enhancement. The new technology identification process consists of R&D issues analysis, technology theme design, and emerging technology sampling. On the other hand, existing service enhancement process has technology landscaping, keyword based search, and technological growth analysis. By implementing these two phase frameworks, we develop a technology portfolio for mobile communication industry.

• Nuclear Engineering and Technology
• /
• v.42 no.2
• /
• pp.163-174
• /
• 2010

As pointed out in the OECD BEMUSE Program, when a high computation time is taken to obtain the relevant output values of a complex physical model (or code), the number of statistical samples that must be evaluated through it is a critical factor for the sampling-based uncertainty analysis. Two alternative methods have been utilized to avoid the problem associated with the size of these statistical samples: one is based on Wilks' formula, which is based on simple random sampling, and the other is based on the conventional nonlinear regression approach. While both approaches provide a useful means for drawing conclusions on the resultant uncertainty with a limited number of code runs, there are also some unique corresponding limitations. For example, a conclusion based on the Wilks' formula can be highly affected by the sampled values themselves, while the conventional regression approach requires an a priori estimate on the functional forms of a regression model. The main objective of this paper is to assess the feasibility of the ACE-RSM approach as a complementary method to the Wilks' formula and the conventional regression-based uncertainty analysis. This feasibility was assessed through a practical application of the ACE-RSM approach to the LOFT L2-5 LBLOCA PCT uncertainty analysis, which was implemented as a part of the OECD BEMUSE Phase III program.

• The KIPS Transactions:PartA
• /
• v.8A no.1
• /
• pp.48-55
• /
• 2001

Using BDD, we can represent Boolean functions uniquely and compactly, Hence, BDD have become widely used for CAD applications, such as logic synthesis, formal verification, and etc. The size of the BDD representation for a function is very sensitive to the choice of orderings on the input variables. Therefore, it is very important to find a good variable ordering which minimize the size of the BDD. Since finding an optimal ordering is NP-complete, several heuristic algorithms have been proposed to find good variable orderings. In this paper, we propose a variable ordering algorithm based on the $\mu$O(microcanonical optimization). $\mu$O consists of two distinct procedures that are alternately applied : Initialization and Sampling. The initialization phase is to executes a fast local search, the sampling phase leaves the local optimum obtained in the previous initialization while remaining close to that area of search space. The proposed algorithm has been experimented on well known benchmark circuits and shows superior performance compared to a algorithm based on simulated annealing.

• Journal of Power Electronics
• /
• v.16 no.5
• /
• pp.1791-1801
• /
• 2016

This paper considers a carrier based signal injection method for use in the three shunt sensing inverter (TSSI) for sensorless motor control. It also analyzes the loss according to the injection axis of the voltage signal. To remove both the phase current and rotor position sensors, a sensorless method and a phase current reconstruction method can be simultaneously considered. However, an interaction between the two methods can be incurred when both methods inject voltage signals simultaneously. In this paper, a signal injection based sensorless method with the 120° OFF Discontinuous PWM (DPWM) is implemented in a TSSI to avoid this interaction problem. Since one leg does not have a switching event for one sampling period in the 120° OFF DPWM, the switching loss is altered according to the injection axis. The switching loss in the d-axis injection case can be up to 32% larger than that in the q-axis injection case. Other losses according to the injection axis are also analyzed.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.2C
• /
• pp.191-200
• /
• 2002

A frequency synthesizer that can be used in IMT-2000 was designed and fabricated using dual loop PLL(Phase Locked Loop) in this paper. For improving phase noise characteristic two loops, reference loop and main loop, were divided. Phase noise was improved by transformed clamp type voltage controled oscillator and optimizing loop bandwidth in reference loop. And voltage controlled oscillator open loop gain in main loop. Fabricated the frequency synthesizer had 1.81GHz center frequency, 160MHz tuning range, 13.5dBm output power and -119.73dBc/Hz low phase noise characteristic.

• Proceedings of the KIEE Conference
• /
• 2007.10c
• /
• pp.135-137
• /
• 2007

In this paper, an advanced torque control scheme of SRM using DITC(Direct Instantaneous Torque Control) and PWM(pulse width modulation) is presented. Different from conventional DITC method, proposed method uses one or two switching modes at every sampling time, instead of only one switching mode. The duty ratio of the phase switch is regulated according to the torque error and simple control rules of DITC. Moreover the sampling time of control can be extended, which allows implementation on low cost microcontrollers. The proposed control method is verified by the simulations and experimental results.