• Journal of Institute of Control, Robotics and Systems
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• v.16 no.7
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• pp.720-725
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• 2010

In AGPS method, user position can be obtained even in the shadow region by improving signal sensitivity. A hybrid long integration scheme employing both coherent and non-coherent integration method is commonly used in AGPS receivers. Because coherent loss increases as residual frequency become large, residual frequency should be minimized to maximize coherent integration gain. This paper presents performance analysis of residual frequency estimator using FFT in fine-time assistance AGPS method. Considering the hardware complexity and the estimation accuracy, optimal length of FFT is proposed for GPS L1 C/A signal. Signal sensitivity for estimating the residual frequency is also analysed. By field experimental results, it is found that the residual frequency can be successfully estimated using 1 second snap-shot data when GPS signal strength is larger than -150 dBm and its RMS error is 3Hz.

• Journal of Communications and Networks
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• v.12 no.3
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• pp.253-265
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• 2010

The problem of pricing for a telecommunication network is investigated with respect to the users' sensitivity to the pricing structure. A functional optimization problem is formulated, in order to compute price reallocations as functions of data collected in real time during the network evolution. No a-priori knowledge about the users' utility functions and the traffic demands is required, since adaptive reactions to the network conditions are sought in real time. To this aim, a neural approximation technique is studied to exploit an optimal pricing control law, able to counteract traffic changes with a small on-line computational effort. Owing to the generality of the mathematical framework under investigation, our control methodology can be generalized for other decision variables and cost functionals.

• Computers and Concrete
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• v.33 no.2
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• pp.147-162
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• 2024

This study presents a random-aggregate mesoscale model integrating the random distribution of the coarse aggerates and the damage mechanics of the mortar and interfacial transition zone (ITZ). This mesoscale model can generate the random distribution of the coarse aggregates according to the prescribed particle size distribution which enables the automation of the current methodology with different coarse aggregates' distribution. The main innovation of this work is to propose the "correction factor" to eliminate the dimensionally dependent mesh sensitivity of the concrete damaged plasticity (CDP) model. After implementing the correction factor through the user-defined subroutine in the randomly meshed mesoscale model, the predicted fracture resistance is in good agreement with the average experimental results of a series of geometrically similar single-edge-notched beams (SENB) concrete specimens. The simulated cracking pattern is also more realistic than the conventional concrete material models. The proposed random-aggregate mesoscale model hence demonstrates its validity in the application of concrete fracture failure and statistical size effect analysis.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.274-280
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• 2005

Future-oriented train design should be able to provide highly refined traffic culture and public transportation service by achieving 'higher value addition, sensitization, and humanization' and then securing safety, convenience, and amenity. Therefore, design of FRT, as a means of environment-friendly public transportation, should have new concepts achieving harmony between design and technology. Consequently, when designing interior of trains for public transportation, it should aim for user-centered strategies. This approach is essentially applied to vehicle design and inducement to new concepts by design aesthetics and their verification become requirements for train Interior design, which should be equipped with sensitivity and functional images. Accordingly, a study on the correlation between constituents in order to implement design is essential to design planning and realization of strategies.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.926-931
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• 2001

In this paper a CAD-based optimal design system is introduced and applied to optimal design of machine tool structures. The system is designed to reduce manual interfacing effort. All the design activities such as selecting design variables, making FE meshes and FE analysis are integrated on a parametric CAD program. A user can easily select design variables by clicking a CAD model. To enhance the robustness and versatility, this system uses the finite difference method for the design sensitivity analysis. By taking a practical example of the design of the column of a horizontal machining center, it is shown that the software system is efficiently usable in industry establishing the goal of minimizing user intervention between various analysis and optimization activities.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.7
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• pp.152-157
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• 2014

Pro-program function of Pro/E has been utilized to expedite the design process of bellows. Design parameters selected for bellows design are manipulated to obtain the shapes user specified. User-oriented function may automate the bellows design process and this function may enable to reduce the design time remarkably. Generated bellows solid model has been applied to study of design sensitivity and optimum design. Among the selected design parameters, thickness of bellows affects system response most. Control-ring installed bellows may reduce the stress and prove to be an effective element for heavy load. The finite element analysis results combined with 3D model generated by pro-program may provide the feasible design directions to the bellows designer.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.409-414
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• 2003

This paper develops a relatively comprehensive and sophisticated constitutive model of concrete for finite element analysis of concrete structures. The present model accounts for the hydrostatic pressure sensitivity and Lode angle dependence behavior of concrete, not only in its strength criterion, but also in its hardening characteristics. The implementation is carried out through incorporating the developed concrete model in User Subroutine Material(UMAT) of the general-purpose FE program ABAQUS(v.5.8). It is found that the model can sufficiently predict the hardening as well as the softening behaviour of concrete under high confining pressure.

• Journal of KIISE
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• v.41 no.12
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• pp.1117-1125
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• 2014

Folksonomy data, which is derived from social tagging systems, is a useful source for understanding a user's intention and interest. Using the folksonomy data, it is possible to create an accurate user profile which can be utilized to build a personalized search system. However there are limitations in some of the traditional methods such as Vector Space Model(VSM) for user profiling and similarity computation. This paper suggests a novel method with graph-based user and document profile which uses the proximity information of query terms to improve personalized search. We demonstrate the performance of the suggested method by comparing its performance with several state-of-the-art VSM based personalization models in two different folksonomy datasets. The results show that the proposed model constantly outperforms the other state-of-the-art personalization models. Furthermore, the parameter sensitivity results show that the proposed model is parameter-free in that it is not affected by the idiosyncratic nature of datasets.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.4
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• pp.186-190
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• 2017

When a product is designed, user's requirements should be well analyzed and applied to the design so that the psychological and aesthetic factors of a product can be accurately conveyed to consumers. The essence of product development is to analyze the changes in the purchasing tendency of consumers and the needs of times, find out user experiences to apply to a design, and establish the objective of product development that well considers those. Designing should be recognized as one that designs even the sensitivity and experience created in the relationship with users, beyond the conventional notion of design that it draws the physical form of a product. As the subjects that design should consider have expanded like this, it has become important that today's design provides a new experience as well as simply develops formative elements based on the functions of an object. As a result, it becomes impossible to accomplish such objective only with the traditional design process that existing designers have stuck to so far. In this respect, this study is aimed to draw out a system and methodology for a user-oriented design process so that design can provide expanded experience to users from product form, applied material, and service.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.43-48
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• 2008

And this study intends to discuss especially the one using emotional filter among various information processing methods. The existing music recommendation service on the web has a weak point that it makes the user feel bored by recommending songs only with similar feeling of the same genre, because music is classified by tune, melody, atmosphere and genre before recommendation. The service using emotion filter, suggested in this study, recommends the song and lyrics appropriate to the current emotional state of the user by abstracting emotional words that could reflect the sensitivity of human and then search the words within lyrics to match in order to overcome the weak point of the existing service. This study starts where the current emotional status for the user is being input. As for the range to choose, there are the seven representatives of emotion which are, love, separation, joy, sorrow-gloom, happiness-lonesome, and anger. As the service receives input of user's emotion, it matches the emotional words appropriate for the emotion input with the lyrics, and ranks the lyrics in the order of priority, so that it recommends the song and it lyrics to the user.