Earticle

Tool marks are critical forensic evidence significantly influencing crime scene interpretation, necessitating continuous research to enhance analysis accuracy. This study applies three-dimensional (3D) shape comparison techniques to analyze impression marks created by tools. Using a 3D microscope, we observed and compared tool marks produced by two types of screwdrivers on metal can lids, confirming the potential of 3D microscopy for tool mark analysis. We developed an objective and accurate method for identifying tool mark similarity by calculating cross-correlation coefficients between 3D shapes of different tool marks. The results demonstrated high similarity between tool marks from the same tool, with maximum cross-correlation coefficients averaging 0.9268575, compared to 0.757101 for marks from different tools, validating the effectiveness of 3D shape analysis for tool mark identification. However, limitations, such as a 0.2 mm measurement error and minor differences in correlation coefficients between matching and non-matching toolmarks, suggest the need for further research into improving the error detection capability and optimizing experimental conditions for enhancing impression mark differentiation.

This study investigates the statistical identity of 3D toolmarks using two types of screwdrivers. Toolmarks were created on dental wax, captured using 2D and 3D microscopes, and analyzed with MATLAB to calculate cross-correlation coefficients and likelihood ratios. Results show that same-tool toolmarks exhibit cross-correlation coefficients centered around 0.9, while different-tool toolmarks center around 0.4. Both 2D and 3D analyses followed a Weibull distribution, confirmed by goodness-of-fit tests. Likelihood ratio calculations demonstrated distinct separation between same-tool and different-tool marks, with 3D analysis showing slightly overlapping ranges due to tool shape-induced depth variations. The study confirms the efficacy of 3D microscopy for toolmark identification, with potential for enhanced 3D analysis through refined techniques and broader data accumulation.

This paper gives an overview of the various approaches to designing statistical pattern recognition scheme based on Bayes discrimination rule and the artificial neural networks for rotating machine condition classification. Concerning to Bayes discrimination rule, this paper contains the linear discrimination rule applied to classification into several multivariate normal distributions with common covariance matrices, the quadratic discrimination rule under different covariance matrices. Also we discribes k-nearest neighbor method to directly estimate a posterior probability of each class. Five features are extracted in time domain vibration signals. Employing these five features, statistical pattern classifier and neural networks have been established to detect defects on rotating machine. Four different cases of rotation machine were observed. The effects of k number and neural networks structures on monitoring performance have also been investigated. For the comparison of diagnosis performance of these two method, their recognition success rates are calculated form the test data. The result of experiment which classifies the rotating machine conditions using each method presents that the neural networks shows the highest recognition rate.

이 연구는 우리나라 해양경찰 통계시스템에 대한 문제점을 살펴보고 바람직한 발전 방향을 모색함에 있어서, 주요 외국의 사례와 비교분석을 통하여 개선할 시사점을 얻는데 목적을 두고 있다. 연구의 완성도를 높이기 위하여 우리나라 해양경찰 통계시스템과 관련된 선행연구를 조사한 후, 비교 대상인 외국의 해양경찰 통계시스템을 조사하였다. 그동안 우리나라 해양경찰의 통계시스템은 수기방식으로 집계ㆍ생산되고 있었다. 그래서 정책부서 간에 중요 데이터의 공유가 원활하지 못하여 해상안전 확보에 필요한 각종 정책을 결정하는데도 어려움이 많았다. 아울러 정책평가를 위한 객관적인 지표로 활용하는데도 한계를 가질 수밖에 없었다. 한편 외국의 경우, 미국 해양경비대는 항만국통계ㆍ해상안전ㆍ해상보안으로 구분하여 통계 수치를 작성하고 있으며, 업무를 처리하는 담당 직원 수 등 구체적인 자료를 재가공할 수 있게 함으로써 정책 수립에 활용하고 있다. 일본 해상보안청은 해상안전관련 통계뿐만 아니라 오염 및 해류 관련 내용까지 수치화하여 해상에서 일어나는 모든 상황을 객관적으로 파악할 수 있는 시스템을 운영하고 있다. 이를 바탕으로 우리나라 해양경찰 통계시스템을 선진화하기 위한 통계항목 등을 개편하고 측정시스템을 보완하는 방향을 제시하였다.

The purpose of this study is to investigate the problems of maritime police statistical system in Korea and to find implications for improvement through comparative analysis of major foreign cases. In order to improve the completeness of the study, we surveyed previous researches related to the Korean Maritime Police Statistical System, and then examined the comparative foreign maritime police statistical system. In the meantime, the statistical system of marine police in Korea has been aggregated and produced by manual method. Therefore, sharing of important data among policy departments was not smooth, and it was difficult to decide various policies necessary for securing maritime safety. In addition, there was a limit to the utilization as an objective indicator for policy evaluation. On the other hand, in the case of foreign countries, the US Maritime Security Service compiles statistical figures by port statistics, maritime safety, and maritime security, and is used for policy formulation by enabling the reprocessing of specific data such as the number of staff members handling the work. The Japan Maritime Safety Agency operates a system that can quantify not only maritime safety statistics but also pollution and ocean currents, so that all situations occurring at sea can be grasped objectively. Based on this, we revised the statistical items to improve the maritime police statistical system in Korea and suggested a direction to complement the measurement system.

뜰개는 해양에서 해수의 특성 및 흐름을 관측하기 위한 장비로서, 해수의 흐름 관측을 이용해 유출유 확산 예측을 위해 사용될 수 있다. 본 논문에서는 관측기관에서 사용하는 뜰개가 특정 시간 간격으로 관측한 바람 및 해수의 특성과 이동경로를 기계학습 기법들을 이용하여 학습시키고 예측하는 모델을 제안한다. 서포트벡터 회귀, 방사기저함수 네트워크, 가우시안 프로세스, 다층 퍼셉트론, 순환신경망을 이용하여 뜰개의 이동경로 예측 방법을 제시한다. 기존 MOHID 수치모델과 비교하여 각 기법별로 4 개의 사례중 3 개에서 성능이 개선되었으며, 가장 좋은 개선율을 보인 기법은 LSTM으로 평균 47.59% 개선되었다. 추후 연구에서는 배깅과 부스팅을 이용하여 가중치를 부여하여 정확도를 개선할 예정이다.

Drifter is an equipment for observing the characteristics of seawater in the ocean, and it can be used to predict effluent oil diffusion and to observe ocean currents. In this paper, we design models or the prediction of drifter trajectory using machine learning. We propose methods for estimating the trajectory of drifter using support vector regression, radial basis function network, Gaussian process, multilayer perceptron, and recurrent neural network. When the propose mothods were compared with the existing MOHID numerical model, performance was improve on three of the four cases. In particular, LSTM, the best performed method, showed the imporvement by 47.59% Future work will improve the accuracy by weighting using bagging and boosting.

본 연구는 초급 한국어 학습자 오류 주석 말뭉치에 나타나는 집단 간 오류 유형별 빈도 차이를 통계적으 로 검증하고 집단에 따른 특정 오류를 파악하는 데 목적이 있다. 이를 위하여 중국 국적의 모국어 중국어 2급 학 습자와 미국 국적의 모국어 영어 2급 학습자의 문어 말뭉치 자료를 연구의 대상으로 삼았다. 두 집단의 오류 유형 별 빈도 차이에 대한 통계적 검증 결과 ‘누락’, ‘첨가’, ‘담화’ 유형에서 유의미한 차이가 나타나는 것을 확인할 수 있었다. 차이가 나타난 세 가지 오류 유형을 세부적으로 살펴 집단별 오류 발생 품사를 제시하면서 집단 간의 차 이와 특성을 제시하였다. 본 연구가 제시한 연구 결과를 기초 자료로 삼아 중국어권, 영어권 학습자의 한국어 습 득 단계 및 단계별 특징에 대한 연구와 검증이 이루어진다면 해당 집단 학습자의 오류를 줄일 수 있는 효율적인 교수법 개발 등으로 나아갈 수 있다.

This study aims at verifying differences in frequency of error types statistically represented in error annotated corpus from basic level Korean language learners and analyzing specific error types between two groups. Prior to analyze, the groups have been selected as the subjects of this study; basic level learners of Chinese native speakers whose nationality is Chinese and English native speakers whose nationality is the United States. According to the result, there was a significant difference in error types of ‘omission’, ‘add’ and ‘discourse’. Following that, based on the parts of speech(POS) of those error types, the differences and characteristics between two groups have been found. If research and verification on Korean language acquisition are conducted based on the research results, it can move on to developing efficient teaching methods that can reduce errors in Chinese and English-speaking group learners.

Cognitive radio is an intelligent wireless technology that increases the spectrum efficiency for its usage. CR enriches wireless technology by utilizing the spectrum holes in order to provide high order quality service to users and to minimize the interference that occurs in the network. In the proposed work, two Spectrum Sensing techniques for Cognitive radio network are used which include Cyclostationary detection and Energy detection techniques. The detection of Cyclostationary signal is not a new term but there is a lot of work to be done in this field. In this paper, the parameter used for Cyclostationary signal is Spectral Correlation function. The detection capability of SCF with different windows is used to check the periodicity of the signal using different windows. Due to the periodicity of the baseband signal, SCF would be able to detect the primary user signal at very low SNR. We also analyze in our work that capability of periodicity of the signal of SCF is not only limited to noise affected signal, perhaps it is also able to detect the attenuated signal. We also simulated Energy detector over MIMO fading channel as it models both Rician fading channel and Rayleigh fading channel. The performance is analyzed in terms of Bit error rate by providing low probability of false alarm and high probability of detection. The Statistical test based comparison is made between the two sensing techniques to evaluate the performance in terms of signal to noise ratio. An extensive set of simulations have been conducted in MATLAB in the proposed work.

The gene encoding carboxymethylcellulase (CMCase) of Bacillus velezensis A-68 was cloned and expressed in Esherichia coli JM109. The optimal concentrations of slats in the medium for cell growth and production of CMCase by E. coli JM109/A-68 were established using statistical methodology. The optimal concentration of K2HPO4, NaCl, MgSO4․7H2O, and (NH4)2SO4 for cell growth of E. coli JM109/A-68 expected by Qualitek-4 (W32b) software (Netek, Inc., USA) were 2.5, 1.0, 0.4, and 0.9 g/L, respectively, whereas those for CMCase were 5.0, 1.5, 0.6, and 0.3 g/L. The optimal concentration of K2HPO4, NaCl, MgSO4․7H2O, and (NH4)2SO4 for cell growth of E. coli JM109/A-68 extracted by Design Expert software (Version 8.0, Stat-Ease Inc., USA) were 4.72, 1.04, 0.46, and 0.85g/L, respectively, whereas those for CMCase were 5.00, 1.50, 0.60, and 0.60 g/L. The optimal concentrations of salt for cell growth of E. coli JM109/A-68 expected by two statistical methods were different from those for production of CMCase.

The optimal concentrations of slats in the medium for cell growth and production of carboxymethylcellulase (CMCase) by Cellulophaga lytica LBH-14 were established using statistical methodology. The optimal concentration of K2HPO4, NaCl, MgSO4․7H2O, and (NH4)2SO4 for cell growth of C. lytica LBH-14 expected by Qualitek-4 (W32b) software (Netek, Inc., USA) were 7.5, 0.5, 0.4, and 0.6 g/l, respectively, whereas those for CMCase were 5.0, 0.5, 0.4, and 0.2 g/L. The optimal concentrations of K2HPO4, NaCl, MgSO4․7H2O, and (NH4)2SO4 for production of cellobiase, which were 5.0, 1.5, 0.2, and 0.6 g/l, respectively, were different from those for production of CMCase. The optimal concentration of K2HPO4, NaCl, MgSO4․7H2O, and (NH4)2SO4 for cell growth of C. lytica LBH-14 extracted by Design Expert software (Version 8.0, Stat-Ease Inc., USA) were 7.50, 0.75, 0.20, and 0.60 g/L, respectively, whereas those for CMCase were 2.50, 0.25, 0.20, and 0.20 g/L. The optimal concentrations of K2HPO4, NaCl, MgSO4․7H2O, and (NH4)2SO4 for production of cellobiase, which were 6.77, 0.64, 0.30, and 0.33 g/l, respectively, were also different from those for production of CMCase.

Previously, all-sky airglow images observed at Shigaraki ($34.9^{\circ}N$, $136.1^{\circ}E$), Japan, during 2004 and 2005 were analyzed in relation to those observed at Mt. Bohyun ($36.2^{\circ}N$, $128.9^{\circ}E$) for a comparison of their gravity wave characteristics (Kim et al. 2010). By applying the same selection criteria of waves and cloud coverages as in the case of Mt. Bohyun all-sky images, we derived apparent wavelengths, periods, phase velocities, and monthly occurrence rates of gravity waves at Shigaraki in this study. The distributions of wavelengths, periods, and speeds derived for Shigaraki were found to be roughly similar to those for Mt. Bohyun. However, the overall occurrence rates of gravity waves at Shigaraki were 36% and 34% for OI 557.7 nm and OH Meinel band airglow layers, respectively, which were significantly higher than those at Mt. Bohyun. The monthly occurrence rates did not show minima near equinox months, unlike those for Mt. Bohyun. Furthermore, the seasonal preferential directions that were clearly apparent for Mt. Bohyun were not seen in the wave propagation trends for Shigaraki. These differences between the two sites imply different origins of the gravity waves near the Korean peninsula and the Japanese islands. The gravity waves over the Japanese islands may originate from sources at various altitudes; therefore, wind filtering may not be effective in causing any seasonal preferential directions in the waves in the airglow layers. Our analysis of the Shigaraki data supports recent theoretical studies, according to which gravity waves can be generated from in situ sources, such as mesosphere wind shear or secondary wave formation, in the mesosphere.

We statistically examined ULF Pc 3-5 wave power in the regions of undisturbed upstream solar wind, quasi-parallel shock (and foreshock), quasi-perpendicular shock, and the magnetosheath to understand how and to what extent the wave power changes as the solar wind propagates to the magnetosheath. For this study, we used the magnetic field data from the THEMIS spacecraft and Wind (as shifted to the bow shock nose) for May-November in 2008 and 2009. The statistical results show that, in the case of the Pc5 wave power, the sheath power is roughly proportional to the upstream power for both quasi-parallel (and foreshock) and quasi-perpendicular shock regions. Also we identified undisturbed upstream condition from WIND as being well away from foreshock region, and found that the sheath power can be larger for quasi-parallel shock region by a factor of 5-15 than for quasi-perpendicular shock region. In the cases of Pc 3 and Pc4 waves, we found the higher sheath power when associated with the foreshock than with the quasi-perpendicular shock region.

년대별로 본 한국인의 성장발육상태를 서로 비교해 봄으로서 얼마나 향상되었나 알아보고자 1910년도부터 1994년까지 각 저자들의 성적을 조사분석한 바 다음과 같은 결론을 얻었다. 1. 신체계측치인 신장, 체중, 흉위, 좌고는 가령에 따라 증가하고 있으나 성장 완료기에서는 각년도별로 점차 증가되었고 특히 1960년 이후 1994년에서는 그 성장이 현저하게 나타났다. 2. 신장과 체중은 평균 10년당 남자의 경우 1.3cm와 1.3kg씩 증가되었으며 여자는 1.6cm와 0.94kg씩 증가하였다(상기의 수치들은 평균증가치임). 3. 성장완료기에 있어서 각 년도별로 성장발육이 증가되었고 특히 1967년, 1983년, 1985년 그리고 1994년에 와서는 현저한 증가를 나타내었다. 이러한 현상은 사회적 경제적 제조건의 향상으로 한국인의 식생활이 좋아졌음으로 성장발육과 체위향상에 많은 영향을 미쳤다는 것을 입증하고 있다.

재조합 균주인 E. coli JM109/DL-3를 사용하여 carboxymethylcellulase를 생산하기 위한 배지의 최적 염 농도를 orthogonal array method (OAM)과 response surface method (RSM) 등과 같은 통계학적인 방법으로 확립하고 그 결과를 비교하였다. OAM에 기초를 한 Qualitek-4 Software를 사용하여 실험을 계획하고, 그 결과를 분석한 결과는 K2HPO4가 균체의 생장 및 carboxymethylcellulase의 생산에 미치는 영향이 가장 크다는 사실을 확인하였다. 균체의 생육에 최적인 $K_2HPO_4$, NaCl, $MgSO_4{\cdot}7H_2O$ 및 $(NH_4)_2SO_4$의 농도는 10.0, 1.0, 0.2 및 0.6 g/l이었으나, carboxymethylcellulase의 생산에 최적인 각 염들의 농도는 각각 5.0, 1.0, 0.4 및 0.6 g/l이었다. RSM에 기초를 한 Design-Expert Software를 사용하여 실험을 계획하고, 그 결과를 분석한 결과는 $K_2HPO_4$가 균체의 생장 및 carboxymethylcellulase의 생산에 가장 중요한 인자라는 사실을 확인하였다. 균체의 생장에 최적인 $K_2HPO_4$, NaCl, $MgSO_4{\cdot}7H_2O$ 및 $(NH_4)_2SO_4$의 농도는 7.44, 1.08, 0.22 및 0.88 g/l이었으나, carboxymethylcellulase의 생산에 최적인 각 염들의 농도는 각각 5.84, 0.69, 0.28 및 0.54 g/l이었다. 기본적으로 OAM에 기초한 software를 사용하여 얻은 결과는 RSM에 기초한 software를 사용하여 얻은 결과와 유사하였다. 최적 조건에서 재조합 균주 E.coli JM109/DL-3이 생산하는 carboxymethylcellulase의 생산은 B. amyloliquifacience DL-에 비하여 1.92배 증가하였다.

The optimal concentrations of salts in medium for cell growth and the production of carboxymethylcellulase (CMCase) by a recombinant E. coli JM109/DL-3 were established using two statistical methods: orthogonal array method (OAM) and response surface method (RSM). The analysis of variance (ANOVA) of data based on OAM indicated that $K_2HPO_4$ gave maximum sum of square (S) and percentage contribution (P) for cell growth as well as production of CMCase. The optimal concentrations of $K_2HPO_4$, NaCl, $MgSO_4{\cdot}7H_2O$, and $(NH_4)_2SO_4$ in medium for cell growth extracted by Qualitek-4 (W32b) Software were 10.0, 1.0, 0.2, and 0.6 g/l, respectively, whereas those for the production of CMCase by E. coli JM109/DL-3 were 5.0, 1.0, 0.4, and 0.6 g/l. The analysis of variance (ANOVA) resulting from RSM indicated that a highly significant salt for cell growth was $K_2HPO_4$ ("probe>F" less than 0.0001), whereas $K_2HPO_4$ and $MgSO_4{\cdot}7H_2O$ were significant for the production of CMCase. The optimal concentrations of $K_2HPO_4$, NaCl, $MgSO_4{\cdot}7H_2O$, and $(NH_4)_2SO_4$ for cell growth extracted by Design Expert Software were 7.44, 1.08, 0.22, and 0.88 g/l, respectively, whereas those for production of CMCase were 5.84, 0.69, 0.28, and 0.54 g/l. The optimal concentrations of salts and their influences on cell growth and production of CMCase extracted by OAM were almost the same as those by RSM. Production of CMCase by a recombinant E. coli JM109/DL-3 under optimized concentration of salts was 1.93 times higher than that by Bacillus amyloliquifaciens DL-3.

The comparison of statistical experiments with a common parameter and parameter space is discussed using the concept of the Blackwell's sufficiency and the Shannon's entropy. Binomial and censored experiments are considered as applications. The loss of information is studied under teh aggregated experiments and truncated experiments, and summerized in some tables which make it possible to indicate the choice of an appropriate experiment.

This paper tried to construct statistical and econometric models on the basis of economic theory in order to discuss the issue of statistical efficiency and unbiasedness including the sample selection bias correcting problem. Comparative analytical tool were one stage Tobit of Maximum Likelihood estimation and Heckman's two-step Tobit of Ordinary Least Squares. The results showed that the adequacy of model for the analysis on demand and choice, we believe that there is no big difference in explanatory variables between the first selection model and the second linear probability model. Since the Lambda, the self- selectivity correction factor, in the Type II Tobit is not statistically significant, there is no self-selectivity in the Type II Tobit model, indicating that Type I Tobit model would give us better explanation in the demand for and choice which is less complicated statistical method rather than type II model.