• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.228-229
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• 2008

In this study, we propose an effective method to improve the clarity and period of the beat in a ring structure. Ring is an simplified model of a Korean bell, in which beating vibration and sound are very important features. An equivalent ring theory is applied and finite element analysis on the equivalent ring is performed to determine the condition of the asymmetric element for the clear and proper period beat. The clarity and the period of the beat are improved by attacking asymmetric mass and decreasing local thickness. Using the equivalent ring, the amount and position of the local variation for the required beat condition are determined and the results are verified by experiment.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1089-1090
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• 2011

This paper presents a novel two-phase two-pole permanent magnet synchronous motor (PMSM) with asymmetric U-core stator structure. The construction and parameters of the novel two-phase U-core PMSM are compared with a conventional U-core single-phase PMSM (SPMSM). Then transient characteristics such as torque, back-emf, and power loss of the both PMSMs are analyzed by using 3-D Finite Element Method (FEM). Under the same condition of rated input current, synchronous speed, similar dimensions and volume, FE results show that the two-phase PMSM with U-core stator has significantly less torque ripple than single-phase U-core PMSM, with similar power loss and efficiency.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.3
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• pp.303-310
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• 1998

We report on the analytical results of examination of fully developed asymmetric flow and heat transfer between parallel plane plates. The asymmetry was introduced by roughening one of the plane while the other was left smooth. The integral method together with a turbulence model based on modified Prandtl's mixing length theory for the rough was used to determine the velocity distribution and friction. The temperature distrtibution is then predicted and heat transfer coefficients are calculated. The present paper shows that the heat transfer increases more than the friction factor for a given roughness structure. Generally the results show the strong effect of asymmetry on engineering parameters. Furthermore it is the roughness structure which influences the nature of asymmetry and heat transfer.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.10-12
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• 2014

In ISO 10140-5:2010, defines the reverberation time conditions of the receiving room. The sound absorption side of test specimen is installed in the source room generally. In this study, examined at the change in the sound insulation characteristics for the test specimen of asymmetric structure attached sound absorbing material by changing the installed position. A difference of sound insulation performance was maxium Rw 1 dB, it is preferable to place the larger sound absorption area in source room.

• Journal of ILASS-Korea
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• v.4 no.4
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• pp.38-45
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• 1999

The near field structure of round turbulent jets with initially asymmetric velocity distribution is investigated experimentally. Experiments were carried out using a constant temperature hot-wire anemometry system to measure streamwise velocity in the jets. The measurements were undertaken across the jet at various streamwise stations in a range starting from the jet exit plane and up to a downstream location of twelve diameters. The experimental results include the distribution of mean and instantaneous velocities, vorticity field, turbulence intensity, and the Reynolds shear stress. The asymmetry of the jet exit plane was obtained by using circular cross-section pipes with a bend at the upstream of the exit. Three pipes were used for this study: A straight pipe, 90 and 160 degree-bended pipes. Therefore, at the upstream of the pipe exit, the secondary flow through the bend and the mean streamwise velocity distribution could be controlled by changing the curvature of pipes.

• Structural Engineering and Mechanics
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• v.40 no.1
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• pp.1-11
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• 2011

Ambient vibration tests were carried out to evaluate the dynamic properties of an asymmetric steel building with semi-rigid connections. The test case has many non-structural elements, constructed in the city of Tehran (Iran). The tests were conducted to obtain natural frequencies, mode shapes and damping ratio of the structure and then Fourier transform were used to analyze the velocity records obtained from the tests. The first and second natural periods of the building were obtained as 1.37 s and 1.28 s through the test and damping ratio for the first mode was calculated as 0.047. However, Natural periods obtained from finite element model have higher values from those gained from ambient vibration. Then the model was calibrated by modeling of the in-fill masonry panels at their exact locations and considering the boundary conditions by modeling two blocks near the block No. 3, but the differences were existed. These differences may be due to some hidden stiffness of nonstructural elements in the low range of elastic behavior, showing the structure stiffer than it is in reality.

• Structural Engineering and Mechanics
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• v.63 no.3
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• pp.281-292
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• 2017

Architecture constraints in buildings may typically cause irregularities in the distribution of stiffness and mass and consequently causes non-compliance of centers of mass, stiffness and strength. Such buildings are known as asymmetric buildings the distribution of strength and stiffness is one of whose main challenges. This distribution is more complicated for concrete buildings with RC shear walls in which stiffness and strength are interdependent parameters. The flexibility under the foundation is another subject that can affect this distribution due to the variation of dynamic properties of the structure and its constituting elements. In this paper, it is attempted to achieve an appropriate distribution pattern by expressing the effects of foundation flexibility on the seismic demand of concrete shear walls and also evaluate the effects of this issue on strength and stiffness distribution among lateral force resistant elements. In order to understand the importance of flexibility in strength and stiffness distribution for an asymmetric building in different conditions of under-foundation flexibility, the assigned value to each of the walls is numerically calculated and eventually a procedure for strength and stiffness distribution dependencies on flexibility is provided.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.5
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• pp.551-560
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• 2003

Particle deposition in human lungs was investigated theoretically by using asymmetric five-lobe lung model. The volumes of each of the five lobes were different, thereby forming an asymmetric lung structure. The tidal volume and flow rate of each lobe were scaled according to lobar volume. The total and regional deposition with various breathing patterns were calculated by means of tracking volume segments and accounting for particle loss during inhalation and exhalation. The deposition fractions were obtained for each airway generation and lung lobe, and dominant deposition mechanisms were investigated for different size particles. Results show that the tidal volume and flow rate have a characteristic influence on particle deposition. The total deposition fraction increases with an increase in tidal volume for all particle sizes. However, flow rate has dichotomous effects: a higher flow rate results in a sharp increase in deposition for large size particles, but decreases deposition for small size particles. Deposition distribution within the lung shifts proximally with higher flow rate whereas deposition peak shifts to the deeper lung region with larger tidal volume. Deposition fraction in each lobe was proportional to its volume. Among the three main deposition mechanisms, diffusion was dominant for particles < 0.5 ${\mu}{\textrm}{m}$ whereas sedimentation and impaction were most influential for larger size particles. Impaction was particularly dominant for particles> 8 ${\mu}{\textrm}{m}$. The results may prove to be useful for estimating deposition dose of inhaled pollutant particles at various breathing conditions.

• The Korean Journal of Applied Statistics
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• v.24 no.5
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• pp.821-831
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• 2011

It has been relatively incomplete in the field of financial time series to adapt asymmetric features to multivar ate GARCH processes (McAleer et al., 2009). Retaining constant conditional correlation(CCC) structure, this article pursues to introduce asymmetric GARCH modelling in analysing multivariate volatilities in time series in a practical point of view. Multivariate Korean financial time series are analyzed in detail to compar our theory with conventional methodologies including GARCH and EGARCH.

• Industrial Engineering and Management Systems
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• v.12 no.3
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• pp.264-273
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• 2013

Credit option is a policy that has been studied by many researchers in the area of supply chain management. This policy has been applied in practice to improve the profits of supply chain members. Usually, a credit option policy is proposed by the seller, and often under a symmetric information environment where members have complete information on each others' operations. In this paper, we investigate two scenarios: firstly, the seller offers a credit option to the buyer, and secondly, the buyer attempts to stretch the length of the credit period offered by the seller. The proposed model in both scenarios will be investigated under an asymmetric information structure where some information are private and are only known to the individual who has knowledge of this information. The interactions between buyer and seller will be modeled by non-cooperative Stackelberg games where the buyer and seller take turn as leader and follower. Among some of the numerical results obtained, the seller and buyer's profits obtained from symmetric information games are larger than those obtained from an asymmetric information game in both scenarios. Furthermore, both buyer and seller's profit in the second scenario are better than in the first scenario.