• 한국축산식품학회지
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• 제44권2호
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• pp.372-389
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• 2024

This study investigated the efficacy of ultraviolet-C (UV-C) irradiation in enhancing the quality of raw bovine milk by targeting microbial populations and lipid peroxidation, both of which are key factors in milk spoilage. We categorized the raw milk samples into three groups based on initial bacterial load: low (<3 Log 10 CFU/mL), medium (3-4 Log 10 CFU/mL), and high (>4 Log 10 CFU/mL). Using a 144 W thin-film UV-C reactor, we treated the milk with a flow rate of 3 L/min. We measured the bacterial count including standard plate count, coliform count, coagulase-negative staphylococci count, and lactic acid bacteria count and lipid peroxidation (via thiobarbituric acid reactive substances assay) pre- and post-treatment. Our results show that UV-C treatment significantly reduced bacterial counts, with the most notable reductions observed in high and medium initial load samples (>4 and 3-4 Log 10 CFU/mL, respectively). The treatment was particularly effective against coliforms, showing higher reduction efficiency compared to coagulase-negative staphylococci and lactic acid bacteria. Notably, lipid peroxidation in UV-C treated milk was significantly lower than in pasteurized or untreated milk, even after 72 hours. These findings demonstrate the potential of UV-C irradiation as a pre-treatment method for raw milk, offering substantial reduction in microbial content and prevention of lipid peroxidation, thereby enhancing milk quality.

• 한국환경보건학회지
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• 제45권2호
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• pp.192-202
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• 2019

Objectives: According to the central limit theorem, the samples in population might be considered to follow normal distribution if a large number of samples are available. Once we assume that toxicity dataset follow normal distribution, we can treat and process data statistically to calculate genus or species mean value with standard deviation. However, little is known and only limited studies are conducted to investigate whether toxicity dataset follows normal distribution or not. Therefore, the purpose of study is to evaluate the generally accepted normality hypothesis of aquatic toxicity dataset Methods: We selected the 8 chemicals, which consist of 4 organic and 4 inorganic chemical compounds considering data availability for the development of species sensitivity distribution. Toxicity data were collected at the US EPA ECOTOX Knowledgebase by simple search with target chemicals. Toxicity data were re-arranged to a proper format based on the endpoint and test duration, where we conducted normality test according to the Shapiro-Wilk test. Also we investigated the degree of normality by simple log transformation of toxicity data Results: Despite of the central limit theorem, only one large dataset (n>25) follow normal distribution out of 25 large dataset. By log transforming, more 7 large dataset show normality. As a result of normality test on small dataset (n<25), log transformation of toxicity value generally increases normality. Both organic and inorganic chemicals show normality growth for 26 species and 30 species, respectively. Those 56 species shows normality growth by log transformation in the taxonomic groups such as amphibian (1), crustacean (21), fish (22), insect (5), rotifer (2), and worm (5). In contrast, mollusca shows normality decrease at 1 species out of 23 that originally show normality. Conclusions: The normality of large toxicity dataset was not always satisfactory to the central limit theorem. Normality of those data could be improved through log transformation. Therefore, care should be taken when using toxicity data to induce, for example, mean value for risk assessment.

• 품질경영학회지
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• 제23권1호
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• pp.41-49
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• 1995

This paper suggests optimal accelerated constant stress life tests in Exponential distribution. The relationship between the log-mean life and the loaded stress is assumed to be linear. Optimal plans considering mean square errors of maximum likelihood estimators of the log mean life and test costs are obtained. We consider accelerated life tests with two stress levels, and as data types, failure censoring( type II) and time censoring(type I) data are used. We propose the procedure to obtain the optimal plans for each case. Some examples are also included.

• Communications for Statistical Applications and Methods
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• 제15권5호
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• pp.775-781
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• 2008

It is developed that a family of the semicircular Laplace distributions for modeling semicircular data by simple projection method. Mathematically it is simple to simulate observations from a semicircular Laplace distribution. We extend it to the l-axial Laplace distribution by a simple transformation for modeling any arc of arbitrary length. Similarly we develop the l-axial log-Laplace distribution based on the log-Laplace distribution. A bivariate version of l-axial Laplace distribution is also developed.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.392-396
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• 2004

The number of parameters and the number of samples are the key point of trans-log cost function which studied recently. Most of models show that the number of parameters is more than the number of samples. Therefore, these studies gave unreliability of the estimation results. First, we surveyed theoretical cases and researches for the formulation of cost function of railroad industry. Second, we will suggest trans-log cost function by analyzing cost data of KNR. And, the cumulative data will be needed for the confidence of estimation results.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1765-1769
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• 2004

The number of parameters and the number of samples are the key point of trans-log cost function which studied recently. Most of models show that the number of parameters is more than the number of samples. Therefore, these studies gave unreliability of the estimation results. First, we surveyed theoretical cases and researches for the formulation of cost function of railroad industry. Second, we will suggest trans-log cost function by analyzing cost data of KNR. And, the cumulative data will be needed for the confidence of estimation results.

• Journal of the Korean Data and Information Science Society
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• 제17권3호
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• pp.963-972
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• 2006

This paper focuses on the likelihood based confidence intervals for two inverse gaussian distributions when the parameter of interest is common scale parameter. Confidence intervals based on signed loglikelihood ratio statistic and modified signed loglikelihood ratio statistics will be compared in small sample through an illustrative simulation study.

• Journal of the Korean Data and Information Science Society
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• 제18권3호
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• pp.767-772
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• 2007

A kernel machine is proposed as an estimating procedure for the linear and nonlinear Poisson regression, which is based on the penalized negative log-likelihood. The proposed kernel machine provides the estimate of the mean function of the response variable, where the canonical parameter is related to the input vector in a nonlinear form. The generalized cross validation(GCV) function of MSE-type is introduced to determine hyperparameters which affect the performance of the machine. Experimental results are then presented which indicate the performance of the proposed machine.

• 한국산림과학회지
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• 제84권2호
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• pp.218-225
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• 1995

이 논문에서는 임업용 트랙터의 집재작업 분석에 요구되는 역학분석모델을 제시하고 사례분석을 통해 적용성을 검토하였다. 역학분석모델은 크게 견인목의 역학구조해석모델, 차량하중분석모델 및 주행중인 차량의 구동력과 저항력 분석모델의 3부분으로 구성되어 있다. 사례분석에서는 가상적인 집재작업 시나리오를 만들어 역학적으로 중요하거나 혹은 집재생산성에 중요한 인자들에 대한 영향력분석을 통해 모델의 적용성을 검토하였다. 사례분석은 1) 당김줄을 견인목에 묶는 방법이 견인력에 미치는 영향, 2)주행속도 및 견인목 하중이 차륜의 동력요구에 미치는 영향, 3) 2륜구동과 4륜구동 트랙터의 견인작업 수행 성능 비교에 관한 내용을 포함한다.

• 융합보안논문지
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• 제5권2호
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• pp.51-56
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• 2005

인터넷의 사용자 증가와 네트워크 환경이 점점 복잡해지고 제공되는 서비스 및 사용자의 요구사항들이 다양해짐에 따라 안정적이고 효과적인 환경을 유지하기 위한 서비스 운용관리는 점점 어려워지고 있다. 또한 초창기 보안은 침입차단시스템에 국한되었지만, 최근에는 침입탐지시스템(IDS), 가상 사설망(VPN), 시스템 보안, 인증 등 관련 솔루션이 대거 등장함에 따라 통합관리가 중요시되어 지고 있다. 이런 문제를 해결하기 위해 제안한 본 로그 분석을 통한 침입 대응시스템은 로그 파일을 XML 형식으로 저장함으로써 XML의 장점인 로그 파일의 검색이 용이하고 빠르게 이루어 질 수 있으며, 데이터의 구조화에 따라 시스템의 로그 파일들을 통합 분석, 관리하는데 이점을 가질 수 있다. 또한, 본 논문에서 제안한 생성된 로그파일을 IP 주소에 의해 소트된 로그와 Port 번호에 의해 소트된 로그, 침입 유형에 의해 소트된 로그, 탐지 시간에 의해 소트된 로그 등 다양한 형태로 변환하기 때문에 다른 침입탐지시스템에서 생성된 로그 파일과 비교 분석이 가능하다.