• Journal of KIISE:Software and Applications
• /
• v.27 no.8
• /
• pp.886-901
• /
• 2000

Verification of the safety of untrusted codes becomes an important issue in the mobile computing environment and the safety-critical software systems. Recently, it is very common to run the codes attached to the electronic mails or downloaded from the web browsers. We propose the verification method of the machine code property. The code producer delivers the machine code and its property, then the code consumer checks whether the delivered code satisfies the delivered property. The safety of source codes is verified by the well-defined compiler systems but the verification mechanism for machine codes is not well defined yet. We design an intermediate language etySECK and propose the verification method of the property of etySECK programs. And then we prove the soundness of our system which is the type system with effect extension.

• Journal of Aerospace System Engineering
• /
• v.15 no.3
• /
• pp.71-78
• /
• 2021

Since most functions of modern aircraft are controlled by software, software errors are directly related to aircraft safety. The criterion in Chapter 15 of the MIL-HDBK-516C addresses safe development and verification of military aircraft software. As the U.S. Air Force repeatedly experienced non-compliance with Chapter 15 criterion of the MIL-HDBK-516C, it published an Airworthiness Circular (AC-17-01) as a guide to meeting the criterion. In this paper, Chapter 15 of MIL-HDBK-516C, AC-17-01 and the SW Qualification Guideline (DO-178C) as applied by the Federal Aviation Administration are compared and analyzed. For the analysis, a matching ratio formula between the MIL-HDBK-516C criteria specified in AC-17-01 and the DO-178C specified in MIL-HDBK-516C criteria is defined. The sections that satisfy MIL-HDBK-516C criterion are derived when AC-17-01 or DO-178C matches. Based on the analysis results, the aircraft software development process is established and examples of application of Chapter 15 of MIL-HDBK-516C are addressed.

• Journal of Electrical Engineering and Technology
• /
• v.12 no.2
• /
• pp.959-968
• /
• 2017

Electrical safety monitoring System (ESMS) is a critical component in modern power systems, which is characterized by large-scale access points, massive users and versatile requirements. For convenience of the information integration and analysis, the software development, maintenance, and application in the system, the cloud platform based ESMS is established and assessed in this paper. Firstly the framework of the system is proposed, and then the assessment scheme with a set of evaluation indices are presented, by which the appropriate cloud product can be chosen to meet the requirements of a specific application. Moreover, to calculate the weights of the evaluation indices under uncertainty, an improved interval AHP method is adopted to take into consideration of the fuzziness of expert scoring, the qualitative consistency test, and the two normalizations in the process of eigenvectors. Case studies have been made to verify the feasibility of the assessment approach for ESMS.

• Advances in concrete construction
• /
• v.9 no.5
• /
• pp.503-510
• /
• 2020

Concrete dams are important structures due to retaining amount of water on their reservoir. So such kind of structures have to be designed against static and dynamic loads. Especially considering on critical importance against blasting threats and environmental safety, dams have to be examined according to the blast loads. This paper aims to investigate structural response of concrete gravity dams under blast loads. For the purpose Sarıyar Concrete Gravity Dam in Turkey is selected for numerical application with its 85 m of reservoir height (H), 255 m of reservoir length (3H), 72 m of bottom and 7 m of top widths. In the study, firstly 3D finite element model of the dam is constituted using ANSYS Workbench software considering dam-reservoir-foundation interaction and a hydrostatic analysis is performed without blast loads. Then, nearly 13 tons TNT explosive are considered 20 m away from downstream of the dam and this is modeled using ANSYS AUTODYN software. After that explicit analyses are performed through 40 milliseconds. Lastly peak pressures obtained from analyses are compared to empirical equations in the literature and UFC 3-340-02 standard which provide unified facilities criteria for structures to resist the effects of accidental explosions. Also analyses' results such as displacements, stresses and strains obtained from both hydrostatic and blasting analysis models are compared to each other. It is highlighted from the study that blasting analysis model has more effective than the only hydrostatic analysis model. So it is highlighted from the study that the design of dams should be included the blast loads.

• Journal of Advanced Navigation Technology
• /
• v.25 no.4
• /
• pp.273-279
• /
• 2021

A flight control computer(FLCC) applied to an unmanned aerial vehicle(UAV) is a safety-critical item, and which is designed in a multiple structure to increase the reliability of operation by securing fault tolerance. These FLCC of multiple structure should be designed so that each independent processing/control components can perform the same operation at the same time. And for this reason, a synchronization algorithm for synchronizing the operation between FLCCs should be included in an operational flight program. In this paper, we propose a software design method for synchronization between dual FLCCs applied to UAVs. The proposed synchronization method is designed to synchronize using only the minimum hardware resources to reduce a failure rate. In addition, the proposed synchronization method is designed to minimized synchronization errors due to a timer operation by designing in consideration of operation characteristics of the hardware timer used for the synchronization.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.50 no.5
• /
• pp.349-357
• /
• 2022

Since the flight control computer of unmanned aerial vehicle (UAV) is a flight critical equipment, it is necessary to ensure reliability and safety from the development step, and a redundancy-based fault management design is required in order to operate normally even a failure occurs. To reduce cost, weight and power consumption, the dual-redundant flight control system design is considered in UAV. However, there are various restrictions on the fault management design. In this paper, we propose the fault detection and isolation designs for the dual-redundant flight control computer to satisfy the safety requirements of an UAV. In addition, the flight control computer developed by applying the fault management design performed functional tests in the integrated test environment, and after performing FMET in the HILS, its reliability was verified through flight tests.

• Geomechanics and Engineering
• /
• v.36 no.5
• /
• pp.489-509
• /
• 2024

Slope stability analysis and prediction are of critical importance to geotechnical engineers, given the severe consequences associated with slope failure. This research endeavors to forecast the factor of safety (FOS) for slopes through the implementation of six distinct ML techniques, including back propagation neural networks (BPNN), feed-forward neural networks (FFNN), Takagi-Sugeno fuzzy system (TSF), gene expression programming (GEP), and least-square support vector machine (Ls-SVM). 344 slope cases were analyzed, incorporating a variety of geometric and shear strength parameters measured through the PLAXIS software alongside several loss functions to assess the models' performance. The findings demonstrated that all models produced satisfactory results, with BPNN and GEP models proving to be the most precise, achieving an R² of 0.86 each and MAE and MAPE rates of 0.00012 and 0.00002 and 0.005 and 0.004, respectively. A Pearson correlation and residuals statistical analysis were carried out to examine the importance of each factor in the prediction, revealing that all considered geomechanical features are significantly relevant to slope stability. However, the parameters of friction angle and slope height were found to be the most and least significant, respectively. In addition, to aid in the FOS computation for engineering challenges, a graphical user interface (GUI) for the ML-based techniques was created.

• Journal of the Korea Society of Computer and Information
• /
• v.29 no.8
• /
• pp.1-9
• /
• 2024

In this paper, we propose a new approach by analyzing driver behavior and gaze changes within the vehicle in real-time to assess and predict the risk of traffic accidents. Utilizing data analysis and machine learning algorithms, this research precisely measures drivers' abnormal behaviors and gaze movement patterns in real-time, and aggregates these into an overall Risk Score to evaluate the potential for traffic accidents. This research underscores the significance of internal factors, previously unexplored, providing a novel perspective in the field of traffic safety research. Such an innovative approach suggests the feasibility of developing real-time predictive models for traffic accident prevention and safety enhancement, expected to offer critical foundational data for future traffic accident prevention strategies and policy formulation.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2009.10a
• /
• pp.379-381
• /
• 2009

In designing full vehicle, crash safety, fuel efficiency, exhaust gas, and driving stability are very important factors. Especially, automotive wheel which supports total vehicle weight is a critical component in view of driving stability. Most of automotive wheel have been manufactured for beautiful appearance by using aluminum alloy in domestic industry. However, the amount of automotive steel wheel used are on an increasing trend according to developing the advanced high strength steel with good formability property recently. In this study, the circumferential deviation of rim with various thickness and yield strength was investigated. The formability evaluation of the rim was developed by using a finite element module furnished by Forge software.

• Proceedings of the Korean Information Science Society Conference
• /
• 2012.06a
• /
• pp.107-109
• /
• 2012

안전필수 소프트웨어는 다양한 분야에 걸쳐 개발과 인증을 위한 표준들이 정의되어 있고, 대부분 프로세스 중심의 인증 방식을 채택하고 있다. 프로세스 중심의 인증 방식의 단점은 제품 소프트웨어의 검증 속성을 보장할 수 없고, 표준에 따라 관점과 관심 속성이 달라서 상호연관이 있는 속성사이의 관계를 기술하는데 적합하지 않다. 본 논문에서, 안전필수 소프트웨어의 표준들의 비교를 통해 특성을 살펴보고, 안전성과 보안 속성을 함께 갖는 안전필수 소프트웨어 개발을 위해, 보증 문서(assurance case) 구성을 목표 설정 표기법(goal structuring notation)으로 작성하고 결과를 고찰한다.