• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2003.10a
• /
• pp.465-472
• /
• 2003

In this paper, the displacement-based seismic design approaches are evaluated utilizing shaking-table test data of a 1:3 scaled reinforced concrete (RC) bearing wall structure Provided by IAEA. The maximum responses of the structure are estimated using the two prominent displacement-based approaches, i.e., the capacity spectrum method and the displacement coefficient method, and compared with the measured responses. For comparison purpose, linear and nonlinear time history analyses and response spectrum analysis are also performed. The results indicate that the capacity spectrum method underestimates the response of the structure In inelastic range while the displacement coefficient method yields reasonable values in general.

• Earthquakes and Structures
• /
• v.22 no.6
• /
• pp.549-559
• /
• 2022

The quasi-static finite element (FE) approaches are widely used for the seismic analysis of tunnels. However, the conventional quasi-static approaches may cause significant deviations when the tunnel excavation process is simulated prior to the quasi-static analysis. In addition, they cannot account for vertical excitations. Therefore, this paper first highlights the limitations of conventional approaches. A hybrid quasi-static FE approach is subsequently proposed and extensively validated for various conditions. The hybrid approach is simple and not time consuming, and it can be used for the preliminary seismic design of tunnels, especially when the tunnel excavation and vertically propagating P-waves are considered.

• Explosives and Blasting
• /
• v.23 no.3
• /
• pp.75-82
• /
• 2005

Many blasting engineers develope their own approach to define how to blast different rockmass properties. The problem is that most of these approaches haven't been formalized in any systematic manner and they depend mainly on casual observation of local conditions by an experienced blaster. In this paper blastability index developed by Lilly is adopted to induce powder factor for blast design considering local conditions. With this approach blastability scheme can be considered joint properties as well as rockmass represented local conditions. This approach is also expected to supplement the shortcomings of existing blast design approaches.

• International Journal of Aeronautical and Space Sciences
• /
• v.1 no.1
• /
• pp.13-20
• /
• 2000

The applications of CFD in the design process of a transonic civil transport at Korea Aerospace Research Institute (KARI) are outlined. Three Navier-Stokes solvers, developed at KARI with different grid approaches, are used to predict the aerodynamic coefficients and solve the flowfield of various configurations. Multi-block, Chimera, and unstructured grids are the approaches implemented. The accuracy of the codes is verified for the transonic flow about RAE wing/fuselage configuration. The multi-block code is used to provide the detailed data on the flowfield around a wall interference model with different test section sizes which will be used in establishing the wall interference correction method. The subsonic and transonic flowfields about K100-04A, one of the configurations of a 100-seater transport developed by KARI and Korea Commercial Aircraft Development Consortium (KCDC), are computed to predict the aerodynamic coefficients. The results for the subsonic flow are compared with those of wind tunnel test, and the agreement is found to be excellent. The interference effect of nacelle installation on the wing of K100-04A is also investigated using the unstructured grid method, and about 10% reduction in wing lift is observed. The accuracy of the three developed codes is verified, and they are used as an efficient tool in the design process of a transonic transport.

• Earthquakes and Structures
• /
• v.7 no.6
• /
• pp.1071-1091
• /
• 2014

Pounding of adjacent structures are always a notable reason for damages after strong ground motions, but it is already unforeseen detail in newly constructed structures. Thus, several approaches have been proposed in order to prevent the pounding of structures. By using optimally tuned mass dampers, it is possible to decrease the displacement vibrations of structures. But in adjacent structures, the response of both structures must be considered in the objective function of optimization process. In this paper, two different designs of Tuned Mass Dampers (TMD) are investigated. The first design covers independent TMDs on both structures. In the second design, adjacent structures are coupled by a TMD on the top of the structures. Optimum TMD parameters are found by using the developed optimization methodology employing harmony search algorithm. The proposed method is presented with single degree of freedom and multiple degree of freedom structures. Results show that the coupled design is not effective on multiple degree of freedom adjacent structures. The coupled design is only effective for rigid structures with a single degree of freedom while the use of independent TMDs are effective on both rigid and flexural structures.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.37 no.3
• /
• pp.247-259
• /
• 2013

This study conceptually approaches and clearly compares the similarities and differences of fashion and architecture through a focus on their correlations. This study identifies the conceptual definitions of functional minimalism by an examination of function that represents the largest similarity between architecture and fashion. This study classifies the nature of functional minimalism and studies cases for each architectural classification in the areas of: the simplicity of a structure, unitarity pursuit of economic value, repeatability in an efficiency unit, reducibility stressing property, and multi-functional spatiality. The characteristics of functional minimalism fashion are distinguish as: simplicity in a structure that highlight structural lines in non-decorated design, unitarity pursuit of economic value represented in united process and pattern for its economic effect, repeatability in an efficiency unit represented through the repeated decoration of a functional unit, reducibility stressing a property that emphasizes property with a dominant design element through a highlight of the characteristics of materials and multi-functional spatiality that represents variability in clothes through an expansion of limited spatial function. This study approaches each discipline with a clear understanding of the differences between the two and suggests standards for a comparative study of architecture and fashion.

• ETRI Journal
• /
• v.38 no.1
• /
• pp.70-80
• /
• 2016

This paper addresses the problem of robust waveform design for distributed multiple-radar systems (DMRSs) based on low probability of intercept (LPI), where signal-to-interference-plus-noise ratio (SINR) and mutual information (MI) are utilized as the metrics for target detection and information extraction, respectively. Recognizing that a precise characterization of a target spectrum is impossible to capture in practice, we consider that a target spectrum lies in an uncertainty class bounded by known upper and lower bounds. Based on this model, robust waveform design approaches for the DMRS are developed based on LPI-SINR and LPI-MI criteria, where the total transmitting energy is minimized for a given system performance. Numerical results show the effectiveness of the proposed approaches.

• Safety and Health at Work
• /
• v.2 no.2
• /
• pp.105-121
• /
• 2011

Objectives: This paper presents the framework and protocol design for a construction industry risk management toolbox. The construction industry needs a comprehensive, systematic approach to assess and control occupational risks. These risks span several professional health and safety disciplines, emphasized by multiple international occupational research agenda projects including: falls, electrocution, noise, silica, welding fumes, and musculoskeletal disorders. Yet, the International Social Security Association says, "whereas progress has been made in safety and health, the construction industry is still a high risk sector." Methods: Small- and medium-sized enterprises (SMEs) employ about 80% of the world's construction workers. In recent years a strategy for qualitative occupational risk management, known as Control Banding (CB) has gained international attention as a simplified approach for reducing work-related risks. CB groups hazards into stratified risk 'bands', identifying commensurate controls to reduce the level of risk and promote worker health and safety. We review these qualitative solutions-based approaches and identify strengths and weaknesses toward designing a simplified CB 'toolbox' approach for use by SMEs in construction trades. Results: This toolbox design proposal includes international input on multidisciplinary approaches for performing a qualitative risk assessment determining a risk 'band' for a given project. Risk bands are used to identify the appropriate level of training to oversee construction work, leading to commensurate and appropriate control methods to perform the work safely. Conclusion: The Construction Toolbox presents a review-generated format to harness multiple solutions-based national programs and publications for controlling construction-related risks with simplified approaches across the occupational safety, health and hygiene professions.

• International Journal of Control, Automation, and Systems
• /
• v.4 no.2
• /
• pp.146-154
• /
• 2006

In this paper, we propose direct and indirect adaptive fuzzy sliding mode control approaches for a class of nonaffine nonlinear systems. In the direct case, we use the implicit function theory to prove the existence of an ideal implicit feedback linearization controller, and hence approximate it to attain the desired performances. In the indirect case, we exploit the linear structure of a Takagi-Sugeno fuzzy system with constant conclusion to establish an affine-in-control model, and therefore design an indirect adaptive fuzzy controller. In both cases, the adaptation laws of the adjustable parameters are deduced from the stability analysis, in the sense of Lyapunov, to get a more accurate approximation level. In addition to their robustness, the design of the proposed approaches does not require the upper bounds of both external disturbances and approximation errors. To show the efficiency of the proposed controllers, a simulation example is presented.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.13-18
• /
• 2003

This paper proposes a design method of PID controllers in the framework of a constrained optimization problem. Owing to the popularity for the controller's simplicity and robustness, a great deal of literature concerning PID control design has been published, which can be classified into frequency-based and time-based approaches. However, both approaches have to be considered together for a designed PID control to work well with a guaranteed closed-loop stability. For this purpose, a penalty function is formulated to satisfy both frequency- and time-domain specifications, and is minimized by a recet nonlinear optimization algorithm to attain optimal PID control gains. The proposed method is compared with Wang's and Ho's methods on a suite of example systems. Simulation results show that the PID control tuned by the proposed method improves time-domain performance without deteriorating closed-loop stability.