• The Journal of the Acoustical Society of Korea
• /
• v.19 no.1E
• /
• pp.13-21
• /
• 2000

In this paper, we present the description and results of experimental study of the sound power measurements based on International Standards ISO 3741 and 3745. The sound power emitted by a calibrated reference sound source was measured in a reverberation room and a free field over a reflecting plane, using the precision methods of International Standards ISO 3741 direct method and ISO 3745, respectively. The sound power measurements carried out in this study give accurate estimation and also show that both methods for determining the sound power levels of a sound source in a reverberation room and a free field over a reflecting plane, according to the ISO 3741 and 3745, respectively, have proved equally good.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.49 no.4
• /
• pp.111-119
• /
• 2012

Time Stretched Pulse (TSP) is used for transmitting and analyzing the impulse signal over the designated spatial place. However, if transfer functions of transmitter and receiver are unknown, performance investigation of free field in temporal domain is barely possible due to the overlap between the direct and indirect signal from the space. Generally, the free field or hemi-free field is evaluated by the Annex A of ISO 3745 in which utilizing the inverse square law with one-third octave band signals. In this paper, the author performs analysis of free field via applying TSP with inverse square law and the results are compared with the one-third octave band signals. According to the analysis of deviation between the corresponding signal and inverse square law model, the proposed TSP method provides the comparable performance index to the one-third octave band signal with reduced measuring time. Provided that the pre-whitening can be implementable by employing the speaker and microphone transfer function, further analyses from TSP compression are able to be performed such as multipath separation from time domain data. The anechoic chamber used in this experiment is verified conformance with ISO 3745 for free field and hemi-free field condition for limited frequency of the signal.

• The Journal of the Acoustical Society of Korea
• /
• v.31 no.4
• /
• pp.225-234
• /
• 2012

The anechoic chamber is essential tool to measure the various acoustic parameters with high precision. The chamber provides the climate controlled indoor environments but requires the dedicated room at a great cost in order to isolate and absorb sound field. Provided the purpose of the chamber is specific to the experiments of sound localization, the performance requirements excluding free field can be alleviated for cost effective solution. This paper designs low cost and profile anechoic chamber based on acoustic pyramids and evaluates the performance specified by the Annex of ISO 3745. Data analysis is employed to measure the free and hemi-free field performance over five straight paths for working areas and four paths for non-working areas. The identical two measurement campaigns were conducted for free and hemi-free field chamber which is easily interchangeable by simple labor in this chamber design. In the working area with conventional speaker, the results of these analyses demonstrate that lab-designed anechoic chamber is in conformance with ISO 3745 for 250 Hz - 16 kHz one-third octave band at free field chamber and for 1 kHz - 16 kHz one-third octave band at hemi-free field chamber.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2012.11a
• /
• pp.1493-1496
• /
• 2012

소프트웨어 생명주기 중 가장 많은 비용이 유지보수 개발에서 발생한다. 대형 소프트웨어 시스템의 운영 유지보수 표준은 ISO/IEC 20000 으로 프로세스통합운영 및 개선활동 중심이어서 유지보수 개발에 대한 SR(Service Request) 처리시 개발 표준 및 구체적 절차가 미비하다. 그러나 대형 소프트웨어 시스템 구축 개발 시 많이 채택하고 있는 CMMI-DEV 표준을 ISO/IEC 20000 유지보수 조직 및 팀원이 내제화를 함으로써 유지보수 개발의 상호 보완적 프로세스로 명세 명확화 및 품질을 제고할 수 있고, 생산성과 효율성을 증대할 수 있다. 따라서 본 연구에서는 ISO/IEC 20000 유지보수 조직이 운영하고 있는 표준절차에 CMMI-DEV 표준 프로세스를 상호보완적으로 매칭한 표준절차를 적용한 통합모델을 제안한다. ISO/IEC 20000 모델의 개발단계에 CMMI-DEV 프로세스 모델을 적용한 통합 모델을 구축하고 실제 프로젝트에 적용하여 본 연구의 실효성을 검증한다.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.15 no.9 s.102
• /
• pp.1092-1099
• /
• 2005

This experimental study deals with the characteristics of LCD or PDP TV set noise, which are differ form those of CRT TV set. These characteristics are most important for establishing the effective method to reduce noise level, searching for the appropriate exposure level and evaluation method of LCD or PDP TV set noise. This study adopt two measurement method to specify the power level of LCD or PDP TV set noise in anechoic room(ISO 3741) and reverberation room(ISO 3745) . Comparing with each results of the two method, the reverberation room method is more simple in measuring and calculating the power level. And the subjective response test are carried out to select the pair of appropriate adjectives to present the characteristics of LCD or PDP TV set noise. The pair of 17 adjectives are selected from the 168 adjectives which are used in presenting the sound and noise form literature.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2016.10a
• /
• pp.449-451
• /
• 2016

차량 내 전기전자제어시스템의 안전성 확보를 위해 2011년 ISO 26262 기능안전 표준이 제정되었다. 조직 내에서는 이 표준을 적용하여 프로세스 구축 및 평가체계를 수립하고 있다. 하지만 ISO 26262 분야에서는 측정지표 기반의 정량적 평가체계 수립 연구 및 사례가 부족하다. 본 연구에서는 PSM 기반의 ISO 26262 기능안전 측정지표 수립방안과 컨셉-시스템-소프트웨어 개발 단계에 적용한 사례를 제시한다. 본 연구를 적용하는 조직에서는 기능안전 활동에 대한 객관적인 평가기준 수립 가이드를 제공받을 수 있을 것으로 기대한다.

• KIPS Transactions on Computer and Communication Systems
• /
• v.5 no.9
• /
• pp.269-274
• /
• 2016

In this paper We focuses on suggestion to quality model for IoT infrastructure services for Internet of Things. Quality model is suggested on security set out in ISO25000 quality factors and assessment of the existing traditional software application of ISO 9126 quality model. We validated that the proposed model can be realized it was applied to evaluate the 4 elements and related security in Metrics.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2020.11a
• /
• pp.698-701
• /
• 2020

여러 대의 자율주행 차량이 하나의 그룹을 형성하여 주행하는 군집주행은 미래 고속도로 교통 시스템의 핵심 기술이다. 이러한 군집주행에서 발생할 수 있는 다양한 상황에서의 안전을 고려하는 일은 단독 자율 주행에서의 경우보다 더 어렵다. 다양한 군집주행의 안전 위협 요인 중, 의도하지 않은 동작으로부터 자율주행 차량의 안전성을 향상하는 방법을 가이드하기 위하여 새로운 표준 ISO/PAS 21448이 제정되었다. 본 논문에서는 ISO/PAS 21448 표준이 다루는 시나리오를 통해 군집주행에서 발생할 수 있는 의도하지 않은 상황의 극복을 위한 방법을 제시하였다. 특히 군집주행 시뮬레이터인 VENTOS를 이용하여 본 논문에서 제시하는 방법이 안전한 군집주행이라는 목표를 달성할 수 있음을 확인하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1998.04a
• /
• pp.735-740
• /
• 1998

Acoustic performance of DICT's acoustic laboratory was evaluated. As a result, background noise and inverse squre law of an anechoic room were satisfied with ISO 3745 standard value. Also, reverberation time and standard deviation of sound pressure level distribution in reverberation rooms were within maximum error limit that was ruled on ISO 3741.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2011.04a
• /
• pp.1331-1332
• /
• 2011

가상사설망(VPN)시스템은 기존 사설망의 고비용과 비효율적인 관리를 해결하기 위해 인터넷망을 마치 전용선으로 사설망을 구출한 것처럼 개발한다. 본 연구에서는 ISO/IEC 9126과 ISO/IEC 25000를 기반을 둔 객관성 있는 품질평가 방법을 구축하고 가상사설망시스템 제품 고유의 보안특성을 접목한 품질평가 체계를 구축함으로써 객관성과 타당성을 갖춘 평가모델을 개발하였다.