• Membrane and Water Treatment
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• v.10 no.1
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• pp.75-82
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• 2019

In a highly urbanized area, land availability is limited for the installation of space consuming stormwater systems for best management practices (BMPs), leading to the consideration of underground stormwater treatment devices connected to the stormwater pipe system. The configuration of a stormwater pipe network determines the hydrological and pollutant transport characteristics of the stormwater discharged through the pipe network, and thus should be an important design consideration for effective management of stormwater quantity and quality. This article presents a multi-objective optimization approach for designing a stormwater pipe network with on-line stormwater treatment devices to achieve an optimal trade-off between the total installation cost and the annual removal efficiency of total suspended solids (TSS). The Non-dominated Sorted Genetic Algorithm-II (NSGA-II) was adapted to solve the multi-objective optimization problem. The study site used to demonstrate the developed approach was a commercial area that has an existing pipe network with eight outfalls into an adjacent stream in Yongin City, South Korea. The stormwater management model (SWMM) was calibrated based on the data obtained from a subcatchment within the study area and was further used to simulate the flow rates and TSS discharge rates through a given pipe network for the entire study area. In the simulation, an underground stormwater treatment device was assumed to be installed at each outfall and sized proportional to the average flow rate at the outfall. The total installation cost for the pipes and underground devices was estimated based on empirical formulas using the flow rates and TSS discharge rates simulated by the SWMM. In the demonstration example, the installation cost could be reduced by up to 9% while the annual TSS removal efficiency could be increased by 4% compared to the original pipe network configuration. The annual TSS removal efficiency was relatively insensitive to the total installation cost in the Pareto-optimal solutions of the pipe network design. The results suggested that the installation cost of the pipes and stormwater treatment devices can be substantially reduced without significantly compromising the pollutant removal efficiency when the pipe network is optimally designed.

• The Journal of Korean Institute of Information Technology
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• v.16 no.11
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• pp.97-103
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• 2018

In this paper, the estimation method for the power signal harmonics is proposed by using the time-varying optimal finite impulse response (FIR) filter. To estimate the magnitude and phase-angle of the harmonic components, the time-varying optimal FIR filter is designed for the state space representation of the noisy power signal which the magnitude and phase is considered as a stochastic process. Since the time-varying optimal FIR filter used in the proposed method does not use any priori information of the initial condition and has FIR structure, the proposed method could overcome the demerits of Kalman filter based method such as poor estimation and divergence problem. Due to the FIR structure, the proposed method is more robust against to the model uncertainty than the Kalman filter. Moreover, the proposed method gives more general solution than the time-invariant optimal FIR filter based harmonic estimation method. To verify the performance and robustness of the proposed method, the proposed method is compared with time-varying Kalman filter based method through simulation.

• Journal of Korean Theatre Studies Association
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• no.40
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• pp.401-450
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• 2010

This thesis purposes to suggest that creative stage directors have copyright ownership and we make them create high-quality of theatre direction. Stage directors are sincere creator of the theatre stage today. We have little judicial precedents about stage directors, no artistic examination related directing. Stage directors are performers who have neighboring rights, there is a problem that they won't have the exclusive right of making derivative works in this country. Others will make creation (such as cinemas, animations, novels) based on stage expression without permission, because stage directors don't have exclusive right of making derivative works. Copyright law can't protect the concept of stage directors and building blocks of them which are drama text, actors and theatre space, because copyright law don't protect idea according to idea/expression dichotomy. The expression of stage direction is belong to five fundamentals which are composition, picturization, movement, rhythm, pantomimic dramatization that are come from Dean & Carra's work. Directors' work is to make theatrical works based on literary works. Therefore, theatrical works are derivative works which based on drama texts. Also, theatrical works are able to be joint works. In the case of that stage directors write drama text and create expression on the stage, they have to own authorship of both works. Merger doctrine should not apply theatre directors' works strictly like any other functional works because stage directors usually create noble expression which have been not before. We need shift of the definition of theatrical works which are derivative works or joint works to protect theatre directors' creativity. Hereafter, the special legal section for dramatic(theatrical) works including the flexible legal definition for performing arts should be established, and 'contract form' for stage directors should be made. Acting edition(literary works) should be published to grant creative directors compensation. I emphasize to grant ownership of copyright to creative stage directors, to encourage directors' works. Therefore, copyright law will be the support for development of cultural arts institutionally.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.1
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• pp.45-53
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• 2019

As the urbanization progresses, the demand for parking in large cities surges compared with that for parking lots. However, the space for securing a parking lot in a large city is physically limited and a budget problem also arises. Therefore, a shared parking system that can utilize existing parking lots is becoming important. This study was carried out to analyze the parking area efficiently for the residents parking area. As a result of the questionnaire survey, it was the most frequent passage to work / commuting and business purposes. The most important factors in parking were 'Parking charge', 'Walking distance to the destination after parking', 'Parking lot searching time' Approximately 46 % of the respondents were female. As a result of the quantitative analysis of the factors influencing the potential use of the intention to use as a dependent variable, it was analyzed that the policy was effective to reduce the parking fee to less than 500 won per 10 minutes and take about 3-6 minutes to search.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5860-5876
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• 2018

A single snapshot data can only provide limited amount of information so that the rank of covariance matrix is not full, which is not adopted to complete the parameter estimation directly using the traditional super-resolution method. Aiming at solving the problem, a joint time delay and angle estimation using matrix pencil method based on information reconstruction vector for orthogonal frequency division multiplexing (OFDM) signal is proposed. Firstly, according to the channel frequency response vector of each array element, the algorithm reconstructs the vector data with delay and angle parameter information from both frequency and space dimensions. Then the enhanced data matrix for the extended array element is constructed, and the parameter vector of time delay and angle is estimated by the two-dimensional matrix pencil (2D MP) algorithm. Finally, the joint estimation of two-dimensional parameters is accomplished by the parameter pairing. The algorithm does not need a pseudo-spectral peak search, and the location of the target can be determined only by a single receiver, which can reduce the overhead of the positioning system. The theoretical analysis and simulation results show that the estimation accuracy of the proposed method in a single snapshot and low signal-to-noise ratio environment is much higher than that of Root Multiple Signal Classification algorithm (Root-MUSIC), and this method also achieves the higher estimation performance and efficiency with lower complexity cost compared to the one-dimensional matrix pencil algorithm.

• Journal of Positioning, Navigation, and Timing
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• v.8 no.3
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• pp.95-105
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• 2019

A method that applies space-time adaptive signal processing (STAP) algorithm based on an array antenna consisting of multiple antenna elements has been known to be effective to remove wide-band jamming signals in GPS receivers. However, the occurrence of phase distortion in navigation signals has been a problem when navigation signals, from which jamming signals are removed using STAP, are supplied to global positioning system (GPS) receivers. This paper verified the navigation performance degradation as a result of phase distortion. To mitigate this phenomenon, this paper proposes a mode switching scheme, in which a bypass mode is adopted to make the best use of the tracking performance of receivers without performing signal processing when jamming signals are not present or weak, and a STAP mode is employed when jamming signals exceed the threshold value. In this paper, the mode switching scheme is proposed for two environments: when receivers are stationary, and when receivers are moving. This paper confirmed that the performance of position error improved because phase distortion could be excluded due to STAP if the bypass mode was adopted under a condition where the jamming signal power level was below the threshold value in an environment where receivers were stationary. However, this paper also observed that the navigation failed due to the instability of tracking performance of receivers due to phase distortion that occurred at the switching time, although the number of switching could be reduced dramatically by proposing a dual threshold scheme of on- and off-thresholds that switched a mode due to the array antenna characteristics of varying gains according to the jamming signal incident direction in an environment where receivers were moving. The analysis results verified that running the STAP algorithm at all times is more efficient than the mode switching, in terms of maintaining stable navigation and ensuring position error performance, to remove jamming signals in an environment where receivers were moving.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.75.2-75.2
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• 2019

Low surface brightness (LSB) dwarf galaxies hold a key to resolve the small-scale problems of Lambda Cold Dark Matter (LCDM) paradigm such as missing satellites problem. Many recent studies found LSB dwarf galaxies around massive galaxies beyond Local Group up to 10Mpc. Motivated by this, we can increase the number of them by searching for LSB dwarf galaxies around galaxies up to 40Mpc. We use stacked deep (${\mu}_R{\sim}26.2mag\;arcsec^{-2}$) optical B, R-band images taken from Maidanak 1.5m telescope, one of facilities of Intensive Monitoring Survey of Nearby Galaxies (IMSNG) which monitored nearby galaxies in a day cadence from 2014 to 2016. Extended LSB sources in ambient regions of 16 nearby galaxies are selected using central surface brightness and total R magnitude criteria. After that, 24 LSB dwarf candidates are selected with visual inspection. To identify if the candidates are satellites or not, we are trying to compare the number density of LSB dwarf candidates around massive galaxies with those in Canada-France-Hawaii-Telescope Legacy Survey (CFHTLS) wide fields which have no dominant massive galaxies for control sample.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.8
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• pp.1095-1101
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• 2020

Vessels or aircraft should be loaded with containers or cargo to maintain weight balance in order to be stable when navigating the route. The container loading algorithm is known as the NP problem and several heuristic methods have been studied. Containers can be characterized by the uniform volume and weight, which makes it easier to find an optimal loading method. In this paper, we propose an algorithm for weight balance when the volume and weight of an object are uniform. It is assumed that the loading space has a special structure of m * n mesh (where m and n are both odd). In this case, we designed a greedy algorithm and proved that the algorithm is optimal in that it can always find a loading position that maintains a weight balance regardless of the number of objects. Our algorithm can be used in many engineering problems, such as loading algorithms and load balancing problems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.1
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• pp.1-7
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• 2020

Fuzzy clustering, represented by FCM(Fuzzy C-Means), is a simple and efficient clustering method. However, the object function in FCM makes clusters affect clustering results proportional to the density of clusters, which can distort clustering results due to density difference between clusters. One method to alleviate this density problem is EDI-FCM(Extended Density-Independent FCM), which adds additional terms to the objective function of FCM to compensate for the density difference. In this paper, proposed is an enhanced EDI-FCM using regularization, Regularized EDI-FCM. Regularization is commonly used to make a solution space smooth and an algorithm noise insensitive. In clustering, regularization can reduce the effect of a high-density cluster on clustering results. The proposed method converges quickly and accurately to real centers when compared with FCM and EDI-FCM, which can be verified with experimental results.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.1
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• pp.54-69
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• 2021

Policy improvement such as the revision of the Road Traffic Act are proposed for personal mobility(especially e-scooter) usage. However, there is not enough discussion to solve the problem of using shared e-scooter. In this study, we analyze the influencing factors that amount of pick-up and drop-off of shared e-scooter by dividing the Seoul into a 200m grid. we develop spatial auotcorrelation model such as spatial lag model, spatial error model, spatial durbin model, and spatial durbin error model in order to consider the characteristics of the aggregated data based on a specific space, and the spatial durbin error model is selected as the final model. As a result, demographic factor, land use factor, and transport facility factors have statistically significant impacts on usage of shared e-scooter. The result of this study will be used as basic data for suggesting efficient operation strategies considering the characteristics of weekday and weekend.