• Journal of Korea Water Resources Association
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• v.52 no.8
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• pp.565-573
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• 2019

An optimization model of water intake planning is developed based on a linear programming (LP) for the intelligent water purification plant operation system. The proposed optimization model minimizes the water treatment costs of raw water purification by considering a time-delay of treatment process and hourly electricity tariff, which is subject to various operation constraints, such as water intake limit, storage tank capacity, and water demand forecasts. For demonstration, the developed model is applied to H water purification center. Here, we have tested three optimization strategies and the results are compared and analyzed in economic and safety aspects. The optimization model is expected to be used as a decision support tool for optimal water intake scheduling of domestic water purification centers.

• Journal of the Economic Geographical Society of Korea
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• v.10 no.4
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• pp.427-443
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• 2007

The purpose of this study is to investigate spacio-temporal structures of traffic flows on the subway network in the Metropolitan Seoul, and the relationships between topological structures of traffic flows and land use patterns. In particular we analyze in the topological structures of traffic flows on the subway network in time dimension as well as in spatial dimension. For the purpose, this study utilizes data mining techniques to the one day T-card transaction data of the last four years, which has developed for exploring the characteristics of traffic flows from large scale trip-transaction databases. The topological structures of traffic flows on the subway network has changed considerably during the last four years. The volumes of traffic flows, the travel time and stops per trip have increased until 2006 and decreased again in 2007. The results are visualized by utilizing GIS and analyzed, and thus the spatial patterns of traffic flows are analyzed. The spatial distribution patterns of trip origins and destinations show substantial differences among time zones during a day. We analyze the relationships between traffic flows at subway stops and the geographical variables reflecting land use around them. We obtain 6 log-linear functions from stepwise multiple regression analysis. We test multicollinearity among the variables and autocollelation for the residuals.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.4
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• pp.37-47
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• 2016

The practical constraints on the commercial FPGAs which contain dedicated wide function multiplexers in their slice structure are incorporated with one of the most advanced FPGA mapping algorithms based on the AIG (And-Inverter Graph), one of the best logic representations in academia. As the first step of the mapping process, cuts are enumerated as intermediate structures. And then, the cuts which can be mapped to the multiplexers are recognized. Without any increased complexity, the delay and area of multiplexers as well as LUTs are calculated after checking the requirements for the tree construction such as symmetry and depth limit against dynamically changing mapping of neighboring nodes. Besides, the root positions of multiplexer trees are identified from the RTL code, and annotated to the AIG as AOs (Auxiliary Outputs). A new AIG embedding the multiplexer tree structures which are intentionally synthesized by Shannon expansion at the AOs, is overlapped with the optimized AIG. The lossless synthesis technique which employs FRAIG (Functionally Reduced AIG) is applied to this approach. The proposed approach and techniques are validated by implementing and applying them to two RISC processor examples, which yielded 13~30% area reduction, and up to 32% delay reduction. The research will be extended to take into account the constraints on the dedicated hardware for carry chains.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.2C
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• pp.246-253
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• 2010

In this paper, a method of removing the space skew and cross-talk cancellation is proposed where the self-generated signals from the subject are used to obtain the subject's location. In the proposed method, the good spatial sound image is maintained even when the listener moves from the sweet spot. Two major parts of the proposed method are as follows: listener position tracking using the stimuli from the subject and removal of the space skew and cross-talk signals. Listener position tracking is achieved by estimation of the time difference of arrival (TDoA). The position of the listener is then computed using the Talyer-series estimation method. The head-related transfer functions (HRTF) are used to remove the space skew and cross-talk signals, where the direction of the HRTF is given by the one estimated from the listener position tracking. The performance evaluation is carried out on the signals from the 100 subjects that are composed of the 50 female and 50 male subjects. The positioning accuracy is achieved by 70%~90%, under the condition that the mean squared positioning error is less than $0.07m^2$. The subjective listening test is also conducted where the 27 out of the 30 subjects are participated. According to the results, 70% of the subjects indicates that the overall quality of the reproduced sound from the proposed method are improved, regardless of the subject's position.

• Science of Emotion and Sensibility
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• v.20 no.1
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• pp.83-94
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• 2017

In this study, we figured out that music modes and item types could affect people's urged decision making through a k-value which results from a delay discounting's hyperbolic function. Generally, high k-value is related to impulsive decision making. Concretely, there was a significant interaction between items and music. For the luxury item, the k-value was higher while listening to major music than minor. However, for the non-luxury item condition the k-value difference was not significant between two pieces of music. Moreover, we expected mood could be manipulated after listening to the music and mediate a difference of tendency. We used first movement as an allegro and second as an andante of Mozart piano concerto No.5 D-major and No.20 D-minor for stimuli. As a result, mode and tempo's main effects were not significant. Nevertheless, there was a significant two-way interaction. To put it concretely, the k-value of major condition was marginally higher than minor condition on allegro. However, the k-value of major condition was significantly lower than minor condition on andante. Also, depressed degree difference was significant but it was not significant as a mediator. Set depressed degree as a predict variable and future time span as a mediator, further research found future time perception partially mediated the effect that depressed degree affects impulsivity.

• Journal of the Korea Institute of Building Construction
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• v.14 no.5
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• pp.379-388
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• 2014

The purpose of this study is to investigate the effect of capsulated slurry phase change material (PCM) on the thermal crack in mass concrete by experimental work and FEM analysis. In this study, three conditions of samples were prepared for evaluating the level of hydration heat, i.e., a material condition, a cement paste condition and a concrete condition. Also, a compressive strength test was conducted for FEM inverse analysis. Based on the results of the experiment, exothermic function coefficients of concrete with encapsulated slurry PCM were deducted by the inverse analysis. After that, they applied to FEM analysis of the mass scale concrete structures. From the results of this experiment, $31^{\circ}C$ capsulated slurry PCM had no super cooling phenomenon in the material condition. In the cement condition, hydration heat decreased by 34.61J when PCM of 1g was mixed. In the concrete condition, PCM of 6% was deducted as the best level in hydration heat absorption. In FEM inverse analysis, rate coefficient of reaction gradually decreased when PCM mixing ratio increased. But, temperature-rise coefficient increased when PCM mixing ratio exceeded 6%. For the inversed exothermic function coefficients applying to large scale concrete structures, a thermal cracking index increased by 0.05 when PCM of 1% was mixed.

• Resources Recycling
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• v.29 no.3
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• pp.11-23
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• 2020

This study aims to investigate breakage and liberation characteristics of iron ore from Shinyemi mine, Jeongseon by ball mill. Parameters of breakage functions for three grade samples of iron ore were obtained using single-sized-feed breakage test and back-calculation based on nonlinear programming. The results showed that with the increase in the grade of iron ore, the breakage rate factor decrease whereas the particle size sensitivity decreases. This results from retardation of microcrack-propagation by magnetite grain in the ore. Breakage distribution analysis showed that the breakage mechanism appear to be impact fracture dominant with the increase of grade owing to the stress distribution effect by magnetite grain. Degree of liberation (DOL) increased with the increase in grade and decrease in particle size, respectively. Using the breakage function and size-DOL relationship, a model that can predict time-dependent-DOL is established. When scale-up factors from operating condition are available, the model is expected to be capable of predicting size and DOL with time in actual mining process.

• Journal of the Korean Institute of Intelligent Systems
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• v.7 no.4
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• pp.48-57
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• 1997

This paper presents the automatic construction and parameter optimization technique for fuzzy logic controllers using genetic algorithm. In general. the design of fuzzy logic controllers has difficulties in the acq~lisition of expert's knowledge and relies to a great extent on empirical and heuristic knowledge which, in many cases, cannot be objectively justified. So, the performance of the controllers c:an be degraded in the case of plant parameter variations or unpredictable incident which a designer may have ignored, and the parameters of fuzzy logic controllers obtained by expert's control action may not be optirnal. Some of these problems can be resolved by the use of genetic algorithm. The proposed method can tune the parameters of fuzzy logic controllers including scaling factors and determine: the appropriate number of fuzzy rulcs systematically. Finally, we provides the second order dead time plant to evaluate the feasibility and generality of the proposed method. Comparison shows that the proposed method can produce fuzzy logic controllers with higher accuracy and a smaller number of fuzzy rules than manually tuned fuzzy logic controllers.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.5
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• pp.188-194
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• 2014

The feature extraction mechanism of the CASA(Computational Auditory Scene Analysis) system uses time continuity and frequency channel similarity to compose a correlogram of auditory elements. In segmentation, we compose a binary mask by using cross-correlation function, mask 1(speech) has the same periodicity and synchronization. However, when there is delay between autocorrelation signals with the same periodicity, it is determined as a speech, which is considered to be a drawback. In this paper, we proposed an algorithm to improve discrimination of channel similarity using Weighted Cross-correlation in segmentation. We conducted experiments to evaluate the speech segregation performance of the CASA system in background noise(siren, machine, white, car, crowd) environments by changing SNR 5dB and 0dB. In this paper, we compared the proposed algorithm to the conventional algorithm. The performance of the proposed algorithm has been improved as following: improvement of 2.75dB at SNR 5dB and 4.84dB at SNR 0dB for background noise environment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.4
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• pp.781-788
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• 2017

This paper proposes a new algorithm for comparing amplitude between multiple digital input signals and its digital logic architecture. After simultaneously comparing multiple inputs, the proposed algorithm can provide the information of the largest (or smallest) value among them by using a simple digital logic function. The drawback of the method is to increase hardware resource. To overcome this we propose a reuse method of the overlapped logic operation. The proposed method focuses on enhancing the operational clock frequency, in other words decreasing combinational delay time. After implementing the comparing method with HDL (hardware description language), we experiment on it with environment of Cyclone III EP3C40F324A7 FPGA of Altera Inc. In case of 4 input signals, it can increase the operational speed as mush as 1.66 times with 1.20 times the hardware resource. In case of 8, it can also have 2.29 times the clock frequency and 2.15 times the hardware resource.