• Fire Science and Engineering
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• v.33 no.3
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• pp.1-8
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• 2019

The international standard for FT-IR gas analysis of fire effluents in ISO 5660-1 cone calorimeter has been being developed in ISO TC 92. A comparison of the round-robin test of WD 21397 was conducted with six participating laboratories in 2018. The test specimens were PMMA, rigid PU foam board, and PVC flooring. The measurement quantities were the time-to-ignition, peak heat release rate, total heat release, and effective heat of combustion for a cone calorimeter test and peak gas concentration, gas generation, and gas yield for FT-IR gas analysis. No outliers were identified. For the cone calorimeter quantities, the repeatability and reproducibility were 1.5% and 9.8%, respectively. For FT-IR gas analysis, the repeatability and reproducibility was 12.9% and 27.9%, respectively.

• The Journal of the Acoustical Society of Korea
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• v.20 no.3
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• pp.56-62
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• 2001

In this paper, we adopt a missing data theory to speech recognition. It can be used in order to maintain high performance of speech recognizer when the missing data occurs. In general, hidden Markov model (HMM) is used as a stochastic classifier for speech recognition task. Acoustic events are represented by continuous probability density function in continuous density HMM(CDHMM). The missing data theory has an advantage that can be easily applicable to this CDHMM. A marginalization method is used for processing missing data because it has small complexity and is easy to apply to automatic speech recognition (ASR). Also, a spectral subtraction is used for detecting missing data. If the difference between the energy of speech and that of background noise is below given threshold value, we determine that missing has occurred. We propose a new method that examines the reliability of detected missing data using voicing probability. The voicing probability is used to find voiced frames. It is used to process the missing data in voiced region that has more redundant information than consonants. The experimental results showed that our method improves performance than baseline system that uses spectral subtraction method only. In 452 words isolated word recognition experiment, the proposed method using the voicing probability reduced the average word error rate by 12％ in a typical noise situation.

• 한국해양학회지
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• v.28 no.3
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• pp.192-201
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• 1993

To reduce tsunami hazards, it is necessary to develope the methods which can simulate tsunami wave signals of coastal areas. In the present paper, it is attempted t use Sign Method for analyzing and simulating recorded tsunami signals. A tsunami record Y(t) can be represented as the convolution integral of a source evolution function E(t') and a wave propagation function K(t-t') Y(t)=.int. E(t')K(t-t')dt' A source function contains the peculiarities of a tsunami generator. A wave function is a kind of transfer function which contains the characteristics of a wave propagation path. The source functions and the wave function and the wave functions of 9 Korean coast points and 6 Japan coast points are estimated, and the tsunami wave signals are simulated by the convolution integrals of the source functions and the wave functions. According to the results of analysis, the Sign Method is an effective method for simulating tsunami wave signals of Korean coast points which are located far from tsunami source areas. Furthermore, if the source function of a neighboring point ad the wave function of an another tsunami are given, unrecorded tsunami wave also can be estimated.

• Fire Science and Engineering
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• v.26 no.2
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• pp.105-111
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• 2012

In this research, aluminum composite panels of the general materials and fire retardant materials as building claddings make researches about fire performance comparison analysis. Test methods of the small and medium cone calorimeter experiments and SBI (Single Burning Item) experiments was applied to the determination. As a result, in the experiments peak heat release rate cone calorimeter the general aluminum composite panel $1,293kW/m^2$ ($75kW/m^2$), flame-retardant aluminum composite panel $70kW/m^2$ ($75kW/m^2$) was measured. In the SBI experiments fire growth rate the general fire aluminum composite panel is approximately 743 W/s and the flame-retardant aluminum composite panel is approximately 97 W/s of the value were measured. Thus, a standards enactment are urgently required in this case it is used as building claddings of the aluminum composite panel by fire risk assessment.

• Korean Aquaculture
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• v.14 no.2
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• pp.52-65
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• 2002

비단가리비의 인공 종묘 생산을 목적으로 전라남도 신안군 대흑산도 주변에 서식하는 비단가리비를 대상으로 인공 종묘 생산을 위한 산란 유발, 수정란의 발생 과정, 유생 사육, 채묘 및 중간 육성 등 양식 생물학적 연구를 실시하였다. 어미의 각종 산란 유발 자극에 대한 반응은 Serotonin 주사, 온도 자극, 혼합 자극에서 반응율이 가장 높았으며, 자외선 조사 해수 자극은 수컷만 반응을 하였고 간출 자극은 반응이 없어 실효성이 없는 것으로 나타났다. 수정란의 크기는 $69.5{\mu}m$이었고, 수정 후 약 2시간에 2 세포기, 8시간 후에 8 세포기, 20시간 후에는 담륜자 유생으로 부화하였으며 40시간 후에는 D상 유생으로 되었다. 수온별 비단가리비 유생의 성장은 수온 $20^{\circ}C$에서 각장 $178.9{\mu}m$로 가장 좋았으며, 이 때의 생존율은 15.5%이었다. 그러나 수온 $15^{\circ}C$에서는 낮은 성장을 보여 각장 $135.9{\mu}m$로 성장하였으며, 생존율도 9.8%로 저조하였다. 수용 밀도별 사육 시험에서 $1m{\ell}$당 1개체와 5개체에서 성장 및 생존율이 양호하여 성장 및 생존율을 볼 때 적정 사육 밀도는 $1m{\ell}$당 5개체 이하로 나타났다. 먹이 생물 종류에 따른 유생의 성장을 알기 위하여 I, gal-baba, C, calcitrans, N, oculata를 단독 또는 혼합으로 공급하였을 때 실험 종료후 각장의 성장은 I, galbana+C. calcitrans+N. oculata구가 $194.2{\mu}$로 가장 좋았고 N. oculata구는 $162.2{\mu}m$로 가장 낮은 성장을 보였다. 생존율에서는 I. galbana+C. calcitransoculata구는 9.4%로 가장 낮은 생존율을 보였다. 채묘기별 유생의 부착률은 염화비닐판을 수평으로 놓은 것과 패각이 각각 3.43%와 3.17%로 가장 양호하였으나, 양파망과 염화비닐판을 수직으로 놓은 것은 각각 1.52%와 1.61%로 비교적 저조하였다. 수정 후 40일째부터 90일째까지 측정한 부착치패의 경과 일수에 따른 각장의 성장은 $SL=184.44e^{0.0335X}(r^2=0.9861)$의 회귀직선식으로서 나타났다. 중간육성 시험에서 수심별 성장을 분석한 결과, 비단가리비 치패는 저층보다 표층이 각장 5.92mm, 전중량 6.07g 정도 더 빨리 성장하였다.

• Journal of the Korean Applied Science and Technology
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• v.29 no.1
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• pp.129-140
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• 2012

Smoke toxicity is the test for the toxicity evaluation of smoke and hazardous gas, caused by combustion of building materials and finishing materials. Smoke toxicity can be evaluated by the mean incapacitation time of mice. This test result can be influenced by the health status of mice and test condition. In acute inhalation toxicity test of hazardous gas, no typical clinical findings and histopathologic abnormalities were observed. Tracheitis and bronchitis as well as acute lung inflammation around terminal bronchiole in some mouse of the highest dose group. Through this study, we established the method for inhalation toxicity test of hazardous gas as well as the SOP of inhalation toxicity test. However, in the future studies, the concentration control methods for inhalation technologies on hazardous gas will be needed to improve continuously and also further studies on other gas inhalation toxicity will be needed to conduct.

• The Journal of the Acoustical Society of Korea
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• v.13 no.1
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• pp.32-41
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• 1994

To solve the frequency variation of speech patterns which consist of LPC sequences, new membership function view from LPC, spectrum and the relations between the order of LPC and spectrum is proposed. To solve the time variation, multi-secation equi-segmentation method which equally divide the speech section into several section are applied. False recognition mainly occur at time when the same syllable is placed at the same utterance. To reduce the error, fuzzy inference is executed using the proposed membership function and weights are assigned into sectional certainty and then the decision method for recognized the section up to the third candidate. To testify the validation of this method, we experimented the recognition test of 28 DDD area names. The recognition rate of the fuzzy inference by the triangle membership function is $92\%$. That of the combined method of the fuzzy inference and the dicision method is $92.9\%$ and that of fuzzy inference by the proposed membership funtion is $93.8\%$.

• Fire Science and Engineering
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• v.28 no.1
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• pp.26-30
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• 2014

A Compensation-type fire detector (CFD) is operated with two functions of a differential-temperature detector and as a fixed-temperature detector. The differential-temperature detector observes a rate of temperature increase, and the fixed-temperature detector measures a given fixed temperature. The differential-temperature detector does not observe the outbreak of fire in slowly increasing temperature conditions, whereas the fixed-temperature detector is not able to observe the outbreak of fire in conditions under predetermined temperature level. We developed a CFD to compensate for weaknesses of both detectors. To compensate for the disadvantages, a sensor of the sensor metal-insulator-transition critical-temperature sensor was used. Temperature coefficient of resistance is the sensitivity for sensor. At $55^{\circ}C$, temperature coefficient of resistance of metal-insulator-transition critical-temperature sensor was 14.15%. Temperature coefficient of resistance of thermistor was about 0.5%. This CFD was operated as two ways that fixed-temperature detector and differential-temperature detector in one sensor.

• Fire Science and Engineering
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• v.30 no.3
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• pp.23-30
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• 2016

A fire extinguishing system for a rack warehouse was recently designed, which only consider the gross area and number of stories. However, the design of such a system should take into account not only the planar structuree, but also the elevation perspectives due to its vertical structure. Moreover, the fire load of the commodities palletized on the racks should be considered, in order to design a performance-based fire safety system that is appropriate for these environmental conditions. For this reason, this study analyzed the fire characteristics of the commodities palletized on the racks (pallet + the commodities in a box unit + vinyl packing material), taking into consideration the results of a field investigation conducted in Korea, as well as the Hazard Classifications of Commodities used in other countries. Through this analysis, the heat release rate (HRR) and smoke production rate (SPR) were derived.

• Journal of KIISE:Databases
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• v.28 no.1
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• pp.15-30
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• 2001

서브시퀀스 매칭은 질의 시퀀스와 유사한 서브시퀀스를 가지는 데이터 시퀀스와 해당 서브시퀀스의 위치를 찾는 문제이다. 본 논문에서는 윈도우를 구성하는 방법의 이원성을 이용한 새로운 서부시퀀스 매칭 방법인 Dual-Match는 윈도우를 구성하는 방법에 있어서 Faloutsos 등이 사용한 방법(간단히 FRM 이라한다)의 이원적 접근법이다. 즉, FRM에서는 데이터 시퀀스를 슬라이딩 윈도우로 나누고 질의 시퀀스를 디스조인트 윈도우로 나누는 방법을 사용한 반면, Dual-Match에서는 데이터 시퀀스를 디스조이트 윈도우로 나누고 질의 시퀀스를 슬라이딩 윈도우로 나누는 방법을 사용한다. FRM은 색인에 필요한 저장공간을 줄이기 위하여 개별 점 대신 최소 포함 사각형만을 저장함으로 인하여 많은 착오해답(유사하지 않은 후보 서브시퀀스)을 발생시켰다. Dual-Match는 FRM과 비슷한 크기의 저장공간에 개별 점을 직접 저장함으로써 이 문제를 해결한다. 실험결과, Dual-Match는 많은 경우에 있어서 FRM에 비하여 후보 개수를 크게 줄이고 성능을 향상시켰다. 특히, 선택률이 낮은 경우($10^{-4}$이하)에는 후보 개수를 최대 8800배 까지 줄이고, 페이지 액세스 횟수를 최대 26.9배까지 줄였으며, 성능을 최대 430배까지 향상시켰다. 또한, 동일한 크기의 색인을 생성하는데 있어서 Dual-Match는 FRM보다 4.10~25.6배 빠르게 색인을 구성하였다. 이는 색인 구성시에 CPU 오버헤드의 많은 부분을 차지하는 저차원 변환의 횟수를 FRM에 비해 크게 줄이기 때문이다. 이 같은 결과로 볼 때, Dual-Match는 대용량 데이터베이스에 대한 서부시퀀스 매칭의 성능을 크게 향상시킬 수 있는 획기적인 연구 결과라 믿는다.