• Proceedings of the KSPS conference
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• 1996.10a
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• pp.514-514
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• 1996

Igbo, a new Benue Congo language has a vowel harmony system which, like that of Akan, is based on the pharynx size or tongue root position. In this study we examine Igbo vowel harmony with particular reference to assimilatory patterns of vowels in different harmony sets. This is to gain some insight into the factors involved in Igbo vowel assimilation, and to establish to what extent reports on Akan vowel assimilation are validated in Igbo. Tokens of the eight phonemic vowels of Standard Igbo are recorded from three native speakers of Igbo. The vowels are acoustically investigated (using the LPC analysis of CSL) in individual lexical items and within carefully designed carrier phrases. The F1 and F2 values of the vowels are obtained as these formant values are generally useful in establishing the salient characteristics of vowels. Vowels from the harmony sets are juxtaposed in the carrier phrases to ascertain the extent of assimilation. Results of the investigation show that the F1 values, to a large extend, are enough to characterize these vowels. The (-Expanded) vowels have higher F1 values than their (+Expanded) counterpart. Where there is an overlap in F1 values for some vowels the F1 bandwidth values serve to distinguish between the vowels. The overlap often reported in Akan for /I/ and /e/ on the one hand and /${\mho}$/ and /o/ on the other is not validated in Igbo. While the F1 values for these pairs of vowels are quite similar for one of our speakers, there is an appreciable difference between the F1 values of these vowels for the other two speakers. There is however an overlap for /e/ and /o/ for one of the speakers. Assimilations are generally regressive across word boundaries. It is, however, necessary to point out that the general perceptual impression that one of the vowels completely assimilates to the other, is not borne out by our investigation. Most of our F1 and F2 values for the vowels in individual lexical items are altered in assimilations. This then suggests that assimilation involving these vowels is partial rather than complete. The emerging 'allophones' are acoustically similar to the (+Expanded) vowel involved in the assimilation, that is when vowels from different harmony sets are involved. We conclude that while assimilation of Igbo vowels involves some phonological considerations, phonetic factors appear to be permanent in deciding the final form of the vowels.

• Structural Engineering and Mechanics
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• v.81 no.1
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• pp.11-28
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• 2022

This paper considers the combination of cyclic and axial loads to investigate the hysteretic performance of H-section 6061-T6 aluminum alloy members. The hysteretic performance of aluminum alloy members is the basis for the seismic performance of aluminum alloy structures. Despite the prevalence of aluminum alloy reticulated shells structures worldwide, research into the seismic performance of aluminum alloy structures remains inadequate. To address this deficiency, we design and conduct cyclic axial load testing of three H-section members based on a reliable testing system. The influence of slenderness ratios and bending direction on the failure form, bearing capacity, and stiffness degradation of each member are analyzed. The experiment results show that overall buckling dominates the failure mechanism of all test members before local buckling occurs. As the load increases after overall buckling, the plasticity of the member develops, finally leading to local buckling and fracture failure. The results illustrate that the plasticity development of the local buckling position is the main reason for the stiffness degradation and failure of the member. Additionally, with the increase of the slenderness ratio, the energy-dissipation capacity and stiffness of the member decrease significantly. Simultaneously, a finite element model based on the Chaboche hybrid strengthening model is established according to the experiment, and the rationality of the constitutive model and validity of the finite element simulation method are verified. The parameter analysis of twenty-four members with different sections, slenderness ratios, bending directions, and boundary conditions are also carried out. Results show that the section size and boundary condition of the member have a significant influence on stiffness degradation and energy dissipation capacity. Based on the above, the appropriate material constitutive relationship and analysis method of H-section aluminum alloy members under cyclic loading are determined, providing a reference for the seismic design of aluminum alloy structures.

• Spatial Information Research
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• v.15 no.2
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• pp.111-121
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• 2007

The GPS positioning offer 3D position using code and carrier phase measurements, but the user can obtain the precise accuracy positioning using carrier phase in Real Time Kinematic(RTK). The main problem, which RTK have to overcome, is the necessary to have a reference station(RS) when using RTK should be generally no more than 10km on average, which is significantly different from DGPS, where distances to RS can exceed several hundred kilometers. The accuracy of today's RTK is limited by the distance dependent errors from orbit, ionosphere and troposphere as well as station dependent influences like multipath and antenna phase center variations. For these reasons, the author proposes Network based GPS Carrier Phase Differential Positioning using Multiple RS which is detached from user receiver about 30km. An important part of the proposed system is algorithm and software development, named DAUNet. The main process is corrections computation, corrections interpolation and searching for the integer ambiguity. Corrections computation of satellite by satellite and epoch by epoch at each reference station are calculated by a Functional model and Stochastic model based on a linear combination algorithm and corrections interpolation at user receiver are used by area correction parameters. As results, the users can obtain the cm-level positioning.

• Journal of Radiation Protection and Research
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• v.39 no.4
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• pp.159-167
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• 2014

In Korea, July 2012, the law as called 'Act on Safety Control of Radioactive Rays Around Living Environment' was implemented to control the consumer product containing Naturally Occurring Radioactive Material (NORM), but, there are no appropriate database and effective dose calculation system. The aim of this study was to develop evaluation technique of the exposure dose with the use of the consumer products containing NORM and to understand the characteristics of the exposed dose according to the radiation type and energy. For the evaluate of exposure dose, the ICRP reference phantom was simulated by the MCNPX code based on Monte Carlo method, and the minimum, medium, maximum energy of alphas, betas, gammas from the representative NORM of Uranium decay series were used as the source term in the simulation. The annual effective doses were calculated by the exposure scenario of the consumer product usage time and position. Short range of the alpha and beta rays are mostly delivered the dose to the skin. On the other hand, the gamma rays mostly delivered the similar dose to all of the organs. The results of the annual effective dose with $1Bq{\cdot}g^{-1}$ radioactive stone-bed and 10% radioactive concentration were employed with the usage time of 7 hours 50 minute per day, the maximum annual effective dose of alphas, betas, gammas were calculated 0.0222, 0.0836, $0.0101mSv{\cdot}y^{-1}$, respectively.

• Journal of radiological science and technology
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• v.45 no.6
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• pp.523-529
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• 2022

Gamma spectroscopy analysis is widely used for radioactivity analysis, and various factors are required for radioactivity calculations. Among the factors, K3 for each sample significantly influences the results. The previous methods of correcting the self-absorption effect include a computational simulation method and a method that requires making a CRM(certified reference material) identical to the sample medium. However, the above methods have limitations when used in small institutions because they require specialized program utilization skills or high manufacturing costs and large facilities. The aim of this study is to develop a method that can be easily and rapidly applied to radioactivity analysis. After filling the beaker with water, we placed the radiation source in a uniform position and used the measured value as the benchmark. Next, a correction factor was derived based on the difference in the radiation source count of the benchmark and the identically measured sample. For the radiation source, Eu-152, which emits a broad range of energy within the measurement range of gamma rays, and Cs-134 and Cs-137, which are indicator nuclides in environmental radiation analysis, were used. The sample was selected within the density range of 0.26-2.11 g/cm³, and the correction factor was derived by calculating the count difference of each sample compared to the reference value of water. This study presents a faster and more convenient method than the existing research methods for determining the self-absorption effect correction, which has become increasingly necessary.

• Journal of Internet Computing and Services
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• v.17 no.4
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• pp.145-159
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• 2016

This study points out the problems of absence of the legislation for standard regulation on Video on Demand(VoD) advertisement which grows so fast lately, for this it recommends making legal references, which have the definition of non-linear broadcasting & VoD advertisement and VoD advertisement standard regulation in the merged Broadcasting Act, and adopting co-regulation system. Pay TV operators providing VoD service have the opportunities to make money as subscribers uses it increasingly. In case of linear service, the Broadcasting Act regulates the advertisement strictly, but not the VoD ads. The reason why is that Korean legislation including the Broadcasting Act does not have legal reference to regulate it, instead of that, it rely on the self-regulation system which is operated by pay-tv players who provide the VoD ads. So, there is the limitation to protect the minors such as children and youth from the harmful VoD ads, to be invulnerable for advertisers to influence to advertising agents, and to ensure the regulatory effectiveness under player-centric self-regulatory regime. In this context, this study analyses the how to regulate VoD ads standard with a three-pronged approach. First, it analyses the VoD ads regulation system in overseas countries, UK, Canada, EU and Ireland. Each country has the legal reference to regulate it in the Broadcasting Act or lower statures and adopts the co-regulatory regime the NRA and the 3rd entity operate together. Second, it reviews the objectives and scope of VoD ads standard. This study recommends that the objective of it is users protection and the scope of it is standard regulation not commercial practice. Third, this study researches how to legislate for regulation of VoD ads standard. Considering VoD service's characteristics(non-linear service) and legal position of Ads agency(i.e. pay tv operators), it suggest that legal reference will be in the integrated Broadcasting bill, which is the general law, not individual. If it is available to regulate VoD ads standard with co-regulatory regime, it expects the enhancement of user protection from the harmful VoD ads and make up sustainability of the pay-tv players' self-regulation.

• Journal of Digital Convergence
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• v.13 no.1
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• pp.297-304
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• 2015

Recently, the demand for a PRT(Personal Rapid Transit) system based on autonomous navigation is increasing. Accordingly, the applicability investigations of the PRT system on rail tracks or roadways have been widely studied. In the case of unmanned vehicle operations without physical guideways on roadways, to monitor the position of the vehicle in real time is very important for stable, robust and reliable guidance of an autonomous vehicle. The Global Positioning System (GPS) has been commercially used for vehicle positioning. However, it cannot be applied in environments as tunnels or interiors of buildings. The PRT navigation system based on magnetic markers reference sensing that can overcome these environmental restrictions and the vehicle dynamics model for its H/W configuration are presented in this study. In addition, the design of a control S/W dedicated for unmanned operation of a PRT vehicle and its prototype implementation for experimental validation on a pilot network were successfully achieved.

• The Journal of Korean Society for Radiation Therapy
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• v.29 no.2
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• pp.101-108
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• 2017

Purpose: The proton used in proton therapy has a characteristic of giving a small dose to the normal tissue in front of the tumor site while forming a Bragg peak at the cancer tissue site and giving up the maximum dose and disappearing immediately. It is very important to verify the proton arrival position. In this study, we used the off-line PET CT method to measure the distribution of positron emitted from nucleons such as 11C (half-life = 20 min), 150 (half-life = 2 min) and 13N The range and distal falloff point of the proton were verified by measurement. Materials and Methods: In the IEC 2001 Body Phantom, 37 mm, 28 mm, and 22 mm spheres were inserted. The phantom was filled with water to obtain a CT image for each sphere size. To verify the proton range and distal falloff points, As a treatment planning system, SOBP were set at 46 mm on 37 mm sphere, 37 mm on 28 mm, and 33 mm on 22 mm sphere for each sphere size. The proton was scanned in the same center with a single beam of Gantry 0 degree by the scanning method. The phantom was scanned using PET-CT equipment. In the PET-CT image acquisition method, 50 images were acquired per minute, four ROIs including the spheres in the phantom were set, and 10 images were reconstructed. The activity profile according to the depth was compared to the dose profile according to the sphere size established in the treatment plan Results: The PET-CT activity profile decreased rapidly at the distal falloff position in the 37 mm, 28 mm, and 22 mm spheres as well as the dose profile. However, in the SOBP section, which is a range for evaluating the range, the results in the proximal part of the activity profile are different from those of the dose profile, and the distal falloff position is compared with the proton therapy plan and PET-CT As a result, the maximum difference of 1.4 mm at the 50 % point of the Max dose, 1.1 mm at the 45 % point at the 28 mm sphere, and the difference at the 22 mm sphere at the maximum point of 1.2 mm were all less than 1.5 mm in the 37 mm sphere. Conclusion: To maximize the advantages of proton therapy, it is very important to verify the range of the proton beam. In this study, the proton range was confirmed by the SOBP and the distal falloff position of the proton beam using PET-CT. As a result, the difference of the distally falloff position between the activity distribution measured by PET-CT and the proton therapy plan was 1.4 mm, respectively. This may be used as a reference for the dose margin applied in the proton therapy plan.

• Journal of the Korea Computer Graphics Society
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• v.23 no.1
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• pp.25-32
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• 2017

This paper proposes a novel acceleration method for particle based large scale fluid simulation. Traditional particle-based fluid simulation has been implemented by interacting with physical quantities of neighbor particles through the Smoothed Particle Hydrodynamics(SPH) technique[1]. SPH method has the characteristic that there is no visible change compared to the computation amount in a part where the particle movement is small, such as a calm surface or inter-fluid. This becomes more prominent as the number of particles increases. Previous work has attempted to reduce the amount of spare computation by adaptively dividing each part of the fluid. In this paper, we propose a technique to calculate the motion of the entire particles by using the physical quantities of the near sampled particles by sampling the particles inside the fluid at regular intervals and using them as reference points of the fluid motion. We propose a technique to adaptively generate a triangle map based on the position of the sampled particles in order to efficiently search for nearby particles, and we have been able to interpolate the physical quantities of particles using the barycentric coordinate system. The proposed acceleration technique does not perform any additional correction for two classes of fluid particles. Our technique shows a large improvement in speed as the number of particles increases. The proposed technique also does not interfere with the fine movement of the fluid surface particles.

• Journal of the Korean Geographical Society
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• v.50 no.1
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• pp.37-52
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• 2015

The purpose of this study is to elucidate the traits of the spatial orientation of urban residents. The analysis materials are the 110 rough maps which have been collected for the last ten years in Yeonsugu, Incheon metropolitan. The urbanites' spatial orientation are analysed from an aspect of the orientation elements and the orientation frames respectively. As a result, the urban dwellers make use of five elements - path, node, district, landmark, and language clue for their spatial orientation. Again the orientation frames of the urban people are investigated in terms of locating and directing in space. In regard to the former, they tend relatively to depend on horizontal axes based on broad streets and to prefer to position at the center on coordinate system. With reference to the latter, they show to be north-at-the-top directed tendency and to hold higher proportion of exocentric perspective than egocentric. Consequently urban residents tend to form spatial orientation with using five spatial elements, leaning horizontal axis, positioning themselves at the central part of coordinates, directing toward north-at-the-top through exocentric perspective.