• Journal of Information Processing Systems
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• v.13 no.1
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• pp.26-39
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• 2017

The need for embedded devices to be able to exchange information with each other and with data centers is essential for the advent of the Internet of Things (IoT). Several existing communication protocols are designed for small devices including the message-queue telemetry transport (MQTT) protocol or the constrained application protocol (CoAP). However, most of the existing implementations are convenient for computers or smart phones but do not consider the strict constraints and limitations with regard resource usage, portability and configuration. In this paper, we report on an industrial research and development project which focuses on the design, implementation, testing and deployment of a MQTT module. The goal of this project is to develop this module for platforms having minimal RAM, flash code memory and processing power. This software module should be fully compliant with the MQTT protocol specification, portable, and inter-operable with other software stacks. In this paper, we present our approach based on abstraction layers to the design of the MQTT module and we discuss the compliance of the implementation with the requirements set including the MISRA static analysis requirements.

• KIPS Transactions on Software and Data Engineering
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• v.9 no.7
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• pp.205-212
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• 2020

Defects are an important factor in the quality of software developments. In order to manage defects, we propose additional information of search and classification. Additional information suggests a systematic classification scheme and method of operation. In this study, we propose additional information at the requirements analysis stage for defect management.

• Journal of the Korea Society of Computer and Information
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• v.6 no.4
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• pp.138-145
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• 2001

In this paper, we propose fuzzy closed BCMP queueing network model for the performance evaluation of distributed processing system. Which has the ambiguous service requirements of job to servers and service rates of server according to network environments. This model can derive the measures for system Performances using fuzzy mean value analysis which can process the fuzzy factors. Computer simulation has been performed for verifying the effectiveness of derived equations of performance evaluation according to service requirements of job and the numbers of clients.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.3
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• pp.395-403
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• 2019

This paper compares the marine engineering courses of two maritime institutions: Mokpo National Maritime University of Korea in the East Asia region and Philippine Merchant Marine Academy in the Southeast Asia region. It shows examines educational marine engineering programs, along with the different divisions and courses at each college. It demonstrates a divergence in methodologies and course offerings to cultivate competitive graduates. The comparative assessment completed is intended to offer broader knowledge on how each institution tackles the requirements of the STCW, and to meet the present and future demands of the maritime industry. Different course offerings are compared along with the units and hours allocated to each subject, and the differences in marine engineering academic and training requirements to graduate. Students must satisfactorily earn 150 units to complete their choice of major. Statistical procedures were used in this assessment and analysis from Excel programs.

• Journal of the Korean Society of Systems Engineering
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• v.14 no.2
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• pp.83-88
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• 2018

Software has become an integral part of almost any system, triggered by the ever-growing demand for automation and artificial intelligent throughout engineering domains. The complexities of software-centric systems are also increasing, which make software test efforts become essential in software development projects. In this study, we applied systems engineering methodology in generating software test cases. We found out the similarities between requirements analysis and traceability concept of systems engineering and test specification contents of software test. In terms of acceptance test, software test cases could be considered as validation requirements. We also suggested a method to determine test order using a SysML modeling tool.

• Annual Conference of KIPS
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• 2004.05a
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• pp.207-210
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• 2004

Waterfall 모델에서의 소프트웨어 개발 단계는 사용자로부터 요구 사항을 정의하고, 이것이 다음 단계의 input 이 되어 개발자에 의해 작업이 진행되는 개발 양식을 따른다. 시스템 요구 사항을 정의할 때에, 프로세스 관점에서 사용자 업무를 이해하고, 이 프로세스에서 사용되는 시스템과의 관계를 정의하여 요구 사항으로 함께 정의한다면, 단순한 시스템의 기능을 정의하여 개발하는 것 보다 시스템의 사용 목적을 이해하고 개발하게 됨으로써, 더 만족도 높은 시스템으로 개발할 수 있게 된다. 프로세스 관점에서 이해하고 정의하는 시스템의 요구 사항은 시스템 보수 작업(Maintenance)시에도 시스템의 상황이 현재 업무 프로세스와 어떻게 연계되어 있는지 파악하기 용이하고, 테스트 단계에서도 테스트 조건이나 테스트 시나리오로서도 활용이 가능하다. 새로운 업무를 담당하는 사람에게도 시스템 개발 요구 사항에서 정의된 업무 프로세스 맵(Map)이 관련 업무를 파악할 수 있는 기초 자료로 재 활용 될 수도 있다. 비즈니스 프로세스 리엔지니어링에서 사용하는 비즈니스 프로세스 맵핑(Mapping) 기술을 소프트웨어 개발 방법론에 적용하여, 요구 분석 단계에서 사용하는 분석 도구로서의 응용을 제안하고자 한다.

• Electronics and Telecommunications Trends
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• v.36 no.4
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• pp.1-12
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• 2021

The competition to lead the next generation of mobile technologies, 6G, is underway while the deployment of 5G has not been implemented worldwide. ITU-R plans to develop technical requirements and standards after completing the 6G Vision by 2023. It can be considered too early to have a concrete view of the 6G core network architecture from this timeline. However, major stakeholders have started making their presence felt by publishing their views. From updated analysis on the technology and service trends proposed, we present a list of research directions on 6G core network from several perspectives: distribution of network functions to nearer edge locations; future fixed-mobile convergence, including low earth orbit satellites; highly-precise QoS guarantee; supporting an extremely wide variety of service requirements; AI-native automation and intelligence; and aligning with the evolution of radio access network.

• Journal of the Korean Society of Systems Engineering
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• v.17 no.2
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• pp.106-113
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• 2021

Today, the market and customer requirements for safety-related products in the Railway industry are continuously increasing, and companies that supply these products continue to make related efforts. However, the international standard requirements for making safety-related products are high, so small and medium-sized business companies are having difficulty developing them due to problems in time and cost to achieve them. This study examined government-centered international certificate policies and cases and suggested improvement measures based on the research results. In addition to supporting international certification costs, the government needs to expand technical consulting and expert training for them to solve problems in obtaining an international certificate.

• Journal of the Korean Society of Systems Engineering
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• v.17 no.2
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• pp.61-68
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• 2021

A decrease in the fertility rate leads to a reduction of troops, so the need to efficiently operate the troops is growing. Therefore, it is necessary to develop a system for estimating warship manpower. In this study, system development was performed according to the CBD methodology. The user requirements were defined and the system function that satisfies the requirements was derived. And through the development process, the CBD methodology and the systems engineering process were compared. As a result, similarities were confirmed in the analysis and concept design stages, so the possibility of merging the two processes was suggested.

• International Journal of Railway
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• v.3 no.3
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• pp.95-105
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• 2010

In this paper, a procedure is proposed to optimize bogie suspension parameters in view of minimizing wheel wear produced by curve negotiation, though meeting stability requirements. The problem is dealt with in the form of a constrained minimization problem, in which wheel wear evaluated over a given service scenario is introduced as the cost function to be minimized, and the requirements on vehicle stability are formulated in terms of constraints. The procedure is applied to the case of a non-powered passenger car for high-speed service, and the results obtained are discussed. It is shown that long wheelbase bogie may provide better overall performances than bogies having comparatively short wheelbase. Furthermore, a sensitivity analysis is performed, to define the effect on the optimization results of improving the performances of the yaw dampers in the bogie and of using a different wheel profile.