• Journal of Institute of Control, Robotics and Systems
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• v.3 no.2
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• pp.187-196
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• 1997

This paper presents a semi-automatic methodology to synthesize executable digital controller saftware in a multi-loop control system. A digital controller is described by a task graph and end-to-end timing requirements. A task graph denotes the software structure of the controller, and the end-to-end requirements establish timing relationships between external inputs and outputs. Our approach translates the end-to-end requirements into a set of task attributes such as task periods and deadlines using nonlinear optimization techniques. Such attributes are essential for control engineers to implement control programs and schedule them in a control system with limited resources. In current engineering practice, human programmers manually derive those attributes in an ad hoc manner: they often resort to radical over-sampling to safely guarantee the given timing requirements, and thus render the resultant system poorly utilized. After task-specific attributes are derived, the tasks are scheduled on a single CPU and the compiled kernel is synthesized. We illustrate this process with a non-trivial servo motor control system.

• Journal of Internet Computing and Services
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• v.12 no.5
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• pp.63-72
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• 2011

Binary translation is a kind of the emulation method which converts a binary code compiled on the particular instruction set architecture to the new binary code that can be run on another one. It has been mostly used for migrating legacy systems to new architecture. In recent, binary translation is used for instrumenting programs without modifying source code, because it enables inserting additional codes dynamically, For general application, there already exists some instrumentation software using binary translation, such as dynamic binary analyzers and virtual machine monitors. On the other hand, in order to be benefited from binary translation in kernel-level, a few issues, which include system performance, memory management, privileged instructions, and synchronization, should be treated. These matters are derived from the structure of the kernel, and the difference between the kernel and user-level application. In this paper, we present a scheme to apply binary translation and dynamic instrumentation on kernel. We implement it on Linux kernel and demonstrate that kernel-level binary translation adds an insignificant overhead to performance of the system.

• Journal of KIISE
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• v.44 no.4
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• pp.363-373
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• 2017

Ext4 file system is widely used in various computing environments such as those of the PC, the server, and the Linux-based embedded system. Ext4, which uses a buffer for block I/O, provides fsync() system call to applications to guarantee the consistency of a specific file. A log of the analytical studies regarding the operation of Ext4 and the improvement of its performance has been compiled, but it has not been studied in detail in terms of kernel versions. We figure out that the behavior of fsync() system call is different depending on the kernel version. Between the kernel versions of 3.4.0 and 4.7.2, 3.4.0, 3.8.0, and 4.6.2 showed behavioral differences regarding the fsync() system call. The latency of fsync() in kernel 3.4.0 is longer than that of the more-advanced 3.7.10; meanwhile, the characteristics of 3.8.0 enabled the disruption of the Ext4 journaling order, but the ordered defect was solved with 4.6.2.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.673-676
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• 2003

In this paper, we designed the embedded system used for wireless LAN communication. Embedded system kernel is made from general linux kernel 2.4.18 by applying the ARM patch (2.4.18-rmk7) and the SA1100 patch(2.4.18-rmk7), then porting board level suitable to target system. The SA-1110 PCMCIA interface provides controls for one PCMCIA card slot with a PSKTSEL pin for support of a second slot. The embedded system requires external logic to complete the PCMCIA socket interface. For dual-voltage support, level shifting buffers are required for all SA-1110 input signals. Hot insertion capability requires that each socket be electrically isolated from each other, and from the remainder of the memory system. embedded system is for socket services approaching PCMCIA socket, detecting number of sockets, sensing insertion and removal, and applying power. It also provides interface with Card services. Embedded system supports Host driver for lucent chips that is installed orinoco driver cross compiled. The meaning can say that is doing wireless LAN communication through wireless LAN in imbedded system.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2609-2611
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• 2003

In this study, we explain the process and the technique required for implementing web-based remote control system based on embedded processor, SAl110, and embedded Linux. At first. cross-compile environment for target system should be constructed on host computer, and bootloader in charge of Linux booting may be loaded on the target system. Then, kernel image is compiled and loaded on the target system. Embedded Linux porting process is completed when ram disk image is generated. Finally, we load wed-server and device driver on the ram disk and make web-page for remote control using CGI. Through the above process, we implement web-based remote control system and present the result.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.4
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• pp.274-279
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• 2015

Wave data acquired over eleven years near Sokcho Harbor located in the central area of the east coast were analyzed using spectral method and wave-by-wave analysis method and its major wave characteristics were examined. Significant wave heights were found to be high in winter and low in summer, and peak periods were also found to be long in winter and short in summer. The maximum significant wave height observed was 8.95 m caused by the East Sea twister. The distributional pattern of the significant wave heights and peak periods were both fitted better by Kernel distribution function than by Generalized Gamma distribution function and Generalized Extreme Value distribution function. The wave data were compiled to subdivide the wave height into intervals for each month, and the cumulative occurrence rates of wave heights were calculated to be utilized for the design and construction works in nearby construction works.

• Computers and Concrete
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• v.33 no.1
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• pp.55-75
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• 2024

The present study introduces an optimum performance soft computing model for predicting the compressive strength of high-performance concrete (HPC) by comparing models based on conventional (kernel-based, covariance function-based, and tree-based), advanced machine (least square support vector machine-LSSVM and minimax probability machine regressor-MPMR), and deep (artificial neural network-ANN) learning approaches using a common database for the first time. A compressive strength database, having results of 1030 concrete samples, has been compiled from the literature and preprocessed. For the purpose of training, testing, and validation of soft computing models, 803, 101, and 101 data points have been selected arbitrarily from preprocessed data points, i.e., 1005. Thirteen performance metrics, including three new metrics, i.e., a20-index, index of agreement, and index of scatter, have been implemented for each model. The performance comparison reveals that the SVM (kernel-based), ET (tree-based), MPMR (advanced), and ANN (deep) models have achieved higher performance in predicting the compressive strength of HPC. From the overall analysis of performance, accuracy, Taylor plot, accuracy metric, regression error characteristics curve, Anderson-Darling, Wilcoxon, Uncertainty, and reliability, it has been observed that model CS4 based on the ensemble tree has been recognized as an optimum performance model with higher performance, i.e., a correlation coefficient of 0.9352, root mean square error of 5.76 MPa, and mean absolute error of 4.1069 MPa. The present study also reveals that multicollinearity affects the prediction accuracy of Gaussian process regression, decision tree, multilinear regression, and adaptive boosting regressor models, novel research in compressive strength prediction of HPC. The cosine sensitivity analysis reveals that the prediction of compressive strength of HPC is highly affected by cement content, fine aggregate, coarse aggregate, and water content.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2D
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• pp.323-334
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• 2011

In this study, we performed the residual geoid modeling using the FFT and LSC methods in context of application of R-R (Remove and Restore) technique as a general technique for gravimetric geoid model in order to propose the effective way of geoid determination in Korea. For this, a number of data compiled for residual geoid modeling by the multi-band spherical FFT method with Stoke's formula and LSC method as known as statistical method. The geometric geoidal heights obtained from 503 GPS/Levelling data were used for inducing the various elements and proper computation process which should be considered for improving the accuracy of residual geoid modeling. Finally, we statistically compared the results of residual geoid heights between FFT and LSC methods and reviewed then the proper way of residual geoid modeling to the region of Korea. As the results of comparison, LSC method is not suitable for residual geoid modeling in Korea due to the noise and lack of gravity observations and the effects of local characteristics, while FFT method by applying Stokes' integral with proper cap size and modified kernel which provides the better accuracy of residual geoid heights up to 10 cm more than those of LSC method.

• Structural Engineering and Mechanics
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• v.67 no.6
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• pp.643-658
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• 2018

In this paper, we introduce a new framework for running the finite element (FE) packages inside an online Loop together with MATLAB. Contrary to the Hardware-in-the-Loop techniques (HiL), in the proposed Software-in-the-Loop framework (SiL), the FE package represents a simulation platform replicating the real system which can be out of access due to several strategic reasons, e.g., costs and accessibility. Practically, SiL for sophisticated structural design and multi-physical simulations provides a platform for preliminary tests before prototyping and mass production. This feature may reduce the new product's costs significantly and may add several flexibilities in implementing different instruments with the goal of shortlisting the most cost-effective ones before moving to real-time experiments for the civil and mechanical systems. The proposed SiL interconnection is not limited to ABAQUS as long as the host FE package is capable of executing user-defined commands in FORTRAN language. The focal point of this research is on using the compiled FORTRAN subroutine as a messenger between ABAQUS/CAE kernel and MATLAB Engine. In order to show the generality of the proposed scheme, the limitations of the available SiL schemes in the literature are addressed in this paper. Additionally, all technical details for establishing the connection between FEM and MATLAB are provided for the interested reader. Finally, two numerical sub-problems are defined for offline and online post-processing, i.e., offline optimization and closed-loop system performance analysis in control theory.