著者
田口 真二
出版者
日本法科学技術学会
雑誌
日本法科学技術学会誌 (ISSN:18801323)
巻号頁・発行日
vol.20, no.2, pp.175-183, 2015 (Released:2015-07-17)
参考文献数
22
被引用文献数
1 1

We selected a group of men who acknowledged sexual interest in prepubescent girls based on the Sexual Desire Scale for Males (SDS-M). Subjects were members of the general population aged 18 years and above who were not in prison (N=573). The relationship between acknowledging sexual interest in prepubescent girls and factors such as their experience of sexual offence, personality traits, cognition towards women and use of pornography were examined. It was estimated that 10% of survey subjects had acknowledged sexual interest in prepubescent girls. Statistical analysis showed that acknowledging sexual interest in prepubescent girls was significantly related to experience of sexual offence against women, some of sexual desire, some of personality traits and acceptance of sexual violence. A significantly higher proportion of men who acknowledged sexual interest in prepubescent girls had experience of sexual offence against women and of using child pornography compared to those who did not. The results of this study suggest that an understanding of sexual interest in prepubescent girls requires the perspectives of cultural and social learning.
著者
田口 真二
出版者
日本法科学技術学会
雑誌
日本法科学技術学会誌 (ISSN:18801323)
巻号頁・発行日
pp.689, (Released:2015-02-17)
参考文献数
22
被引用文献数
1

We selected a group of men who acknowledged sexual interest in prepubescent girls based on the Sexual Desire Scale for Males (SDS-M). Subjects were members of the general population aged 18 years and above who were not in prison (N=573). The relationship between acknowledging sexual interest in prepubescent girls and factors such as their experience of sexual offence, personality traits, cognition towards women and use of pornography were examined. It was estimated that 10% of survey subjects had acknowledged sexual interest in prepubescent girls. Statistical analysis showed that acknowledging sexual interest in prepubescent girls was significantly related to experience of sexual offence against women, some of sexual desire, some of personality traits and acceptance of sexual violence. A significantly higher proportion of men who acknowledged sexual interest in prepubescent girls had experience of sexual offence against women and of using child pornography compared to those who did not. The results of this study suggest that an understanding of sexual interest in prepubescent girls requires the perspectives of cultural and social learning.
著者
財津 亘 渋谷 友祐 長谷川 直宏
出版者
日本法科学技術学会
雑誌
日本法科学技術学会誌 (ISSN:18801323)
巻号頁・発行日
vol.13, no.1, pp.83-92, 2008 (Released:2008-04-19)
参考文献数
28

Offender profiling is one of the tools of decision making for criminal investigation. It is a set of techniques to infer characteristics of an unknown offender, such as sex, age bracket, lifestyle, psychological feature, previous crime, inhabited area, from the information which is left at the crime scene.   In this article, we proposed a tool of decision-making for criminal investigation from the perspective of prediction of an uncertain event by the use of a Bayesian Network (BN). BN is a probability model that describes causal structure of events as chain networks of conditional probability, and is capable to predict the possibility of uncertain events.   To examine the validity of the constructed model, firstly, we divided previous offenders’ information of the indoor-sex-offence cases into a training data (9,859 cases) and validation data (50 cases). Secondly, we constructed a model from the training data by means of K2 and MDL (minimum description length) as search-algorithm and information criteria, respectively. Finally, the validity of the model was examined by the validation data as virtual cases.   According to the model, 21 target variables (16 behavioral variables, 2 vehicle variables and 3 victim variables) linked the explanatory variable (employment) directly, and most of these variables related to the employment. The results of the model validity showed that the accuracy of predicting the employment increased 10% higher when the age bracket could be estimated from the testimony of the victim.   The results indicated that the BN model of the offender profiling would be able to provide valuable information for decision making for crime investigation. To predict characteristics of an unknown offender more accurately, it is crucial to select more appropriate information criteria and develop the search-algorithm, as well as to construct the database from more accurate information.
著者
横田 賀英子 大塚 祐輔 倉石 宏樹 和智 妙子 渡邉 和美
出版者
日本法科学技術学会
雑誌
日本法科学技術学会誌 (ISSN:18801323)
巻号頁・発行日
vol.19, no.1, pp.19-30, 2014 (Released:2014-02-04)
参考文献数
15

Characteristics of male offenders arrested in Japan for exhibitionism (N = 414) and features of their offences were investigated. In analyses, their behavioral consistency was also examined by focusing on 87 repeat exhibitionists. The results indicated that many offenders were well-adjusted persons: 71% were employed, 30% were married, and 23% were graduates. Moreover, 66% of the offences were committed in daytime, and 64% targeted victims aged 10-20 years. In 24% of cases, the distances between offenders' residences and crime scenes were less than one kilometer, whereas 40% of offenders lived over 5 kilometers away. In terms of behavioral consistency, offences in “trains or buses” and public spaces were shown to be consistent for repeated arrests, even after taking the occurrence rate into consideration by measures of adjusted standardized residual (ASR) and forward specialization coefficient (FSC), which is suggestive of behavioral consistency. Finally, less frequent behaviors, such as nighttime offences and offences targeting victims aged 30 years or older occurred less consistently in the series of offences. The results suggested that many exhibitionists rationally decided when and where to commit crimes, based on their calculation of risk and reward. The fact that many offenders were well-adjusted persons might be one of factors explaining offender's rational decision making. The findings in the current study can contribute to the police investigation to prioritize their investigative targets. The current research can form the basis of understanding of the nature of male exhibitionists.
著者
財津 亘
出版者
日本法科学技術学会
雑誌
日本法科学技術学会誌 (ISSN:18801323)
巻号頁・発行日
vol.13, no.2, pp.133-142, 2008 (Released:2008-10-17)
参考文献数
30

The relationship between serial rapist type and the time interval from the first to the second crime was investigated in Study 1. A Bayesian Network (BN) model, included rapists' type derived in Study 1 and the time interval from the first to the second crime, was constructed to predict the time interval till the second crime, and this model was tested in Study 2.   In Study 1, 147 serial rapists were classified according to the severity of the rapists' criminality by using categorical principal components analysis (CatPCA). Results indicated that the interval from the first to the second crime for rapists with a low severity of the criminality (mean 158.0 days) was longer than that for rapists with a high severity of the criminality (mean 82.1 days). In Study 2, A BN model was constructed from the following variables: rapists' characteristic derived in Study 1 (the severity of the criminality), time interval from the first to the second crime, as well as criminal behaviors. The model was tested by using new data, 20 serial rapists committed, as virtual cases. The results of model estimation indicated that the accuracy of predicting the time interval from the first to the second crime, either within 42 days or later, was 80.0%. In detail, if the model predicted that a rapist would commit the second crime in less than 42 days, the accuracy of the prediction was 75.0%, whereas if the model predicted that a rapist would commit the second crime in over 42 days, the accuracy of the prediction was 87.5%.
著者
戸山 恭平 平島 昭雄 竹下 尚紀 西嶋 靖治
出版者
日本法科学技術学会
雑誌
日本法科学技術学会誌 (ISSN:18801323)
巻号頁・発行日
vol.18, no.1, pp.23-33, 2013 (Released:2013-02-20)
参考文献数
15
被引用文献数
1

In order to estimate type and trajectory of the fired bullet from the analysis of the ricochet mark, we carried out the gunfire test against the inclined target. 1.2 mm thin steel plates were used as intermediate targets in this study. The following are types of cartridges which were used: 25 AUTO., 32 AUTO., 7.62 mm Tokarev, 380 AUTO., 38 SPL. (FMC), 38 SPL. (LRN), 9 mm Luger and 45 AUTO.. The target was put in a wooden frame. The angle of incidence was changed by rotating the wooden frame.   We could classify the deformation morphology on the thin steel plate into 4 patterns: Ricochet mark without the crack (Type 1), Ricochet mark with the small crack (Type 2), Ricochet mark with the large crack (Type 3), Penetration (Type 4). Metal from the bullet surface was left on the surface of the target. It was thought that the crack in the edge of the ricochet mark (Type 2 or 3) was caused by the friction arising from the rifling rotation of the fired bullet. The length of the ricochet mark in the longitudinal direction L increases with increase of the kinetic energy of the bullet E. The value of L was relative to the kinetic energy resolved into the horizontal component of the velocity Ecos2θi (θi: the angle of incidence). Except for 380 AUTO. and 38 SPL., the value of L was almost independent of E and Ecos2θi respectively. The ratio of the angle of ricochet θr to the angle of incidence θi was around 1 to 2. Therefore, caliber and type of a fired bullet and the trajectory can be determined from the analysis of the ricochet mark and the contour when the bullet is fired into a 1.2 mm thin steel plate.
著者
財津 亘 金 明哲
出版者
日本法科学技術学会
雑誌
日本法科学技術学会誌 (ISSN:18801323)
巻号頁・発行日
pp.678, (Released:2014-10-31)
参考文献数
28
被引用文献数
1

The effectiveness of identifying the author of an illegal document by using text mining was investigated. The suspected writing evaluated in this study was a claim of responsibility written by a 14-year-old boy, which stated that he committed the “Kobe child murders” in 1997. It was compared with control writings including confessions, and an essay that we knew were written by the same boy, as well as with irrelevant materials including various essays written by five junior high school students, and claims of responsibility in four past criminal cases. First, the writings in each document were digitalized and converted to text files. Then, the relative frequencies of bigram of letters, bigram of part-of-speech taggers, sentence lengths of each document, and rate of using Kanji, Hiragana, and Katakana were calculated. Results of sammon multi-dimensional scaling and hierarchical cluster analysis indicated that the text in the suspected writing was arranged identically or similarly to groups of texts in control materials, where they were arranged differently from groups of texts in irrelevant materials. In a separate analysis, the suspected writing was substituted with a document written by a different offender and we conducted the identical procedure described above. Results demonstrated that texts in the suspected writing were in a different form control and irrelevant texts. These results indicated the effectiveness of identifying an author by using text mining when examining forensic documents.
著者
高林 豊 渡邉 信光 岩本 文夫
出版者
日本法科学技術学会
雑誌
日本法科学技術学会誌 (ISSN:18801323)
巻号頁・発行日
vol.12, no.2, pp.197-206, 2007 (Released:2007-10-06)
参考文献数
8

The mechanism of starting a fire from a kerosene fan heater by misusing of gasoline is similar to that from a wich-type kerosene heater. However, a combustion control device and many safety devices of a kerosene fan heater are different from those of a kerosene heater. Therefore, it is necessary to elucidate an outbreak of fire risk by these differences.   In this work, an outbreak of fire risk of a kerosene fan heater by misusing of gasoline was examined through combustion experiments. Then, we confirmed that the mechanism of starting a fire from a kerosene fan heater require fuel leakage as well as a kerosene heater. The difference of the structure of a kerosene fan heater influenced the outbreak of fire mechanism. And a flame sensor that is one of the safety devices was found to detect misusing of gasoline. Moreover, the GC analysis of each component of a burnt-out kerosene fan heater was found to be effective to prove misusing of gasoline.
著者
Takaya Murakami Yoshiaki Iwamuro Reiko Ishimaru Satoshi Chinaka Ippei Noda Shuhei Higashibayashi Nariaki Takayama
出版者
日本法科学技術学会
雑誌
日本法科学技術学会誌 (ISSN:18801323)
巻号頁・発行日
pp.722, (Released:2017-04-28)
参考文献数
22
被引用文献数
1

We present herein a practical methodology for elucidating the o-, m-, or p-fluorine substitution pattern of indazole-type synthetic cannabinoids containing a fluorobenzyl group at the N-1 position and a carbonyl group at the C-3 position via electron ionization-triple quadrupole mass spectrometry. We synthesized, as model compounds of the synthetic cannabinoids, the o-, m-, and p-fluorine positional isomers: 1-[1-(2-, 3-, and 4-fluorobenzyl)-1H-indazol-3-yl]ethanone (o-, m-, and p-FUBINAE). Mass spectral analyses showed that the three isomers differed significantly in the logarithmic values of the abundance ratios of the product ion at m/z 109 to the precursor ion at m/z 253 (ln(A109/A253)), following the order of meta<ortho<para. In addition, the relationships between ln(A109/A253) and collision energy were linear with high correlation coefficients. Comparing the ln(A109/A253) plots of the FUBINAE isomers versus collision energy with similar plots of AB-FUBINACA and its o- and m-fluorobenzyl isomers showed that the three AB-FUBINACA isomers behaved as the FUBINAE isomers did with the same fluorine substitution pattern on the phenyl ring. Moreover, other synthetic cannabinoids with a p-fluorobenzyl group (ADB-FUBINACA, FUB-AMB, FUB-APINACA, FUB-NPB-22, and FU-PX-2) also exhibited behavior similar to p-FUBINAE. These results indicated that the fluorine substitution position on the phenyl ring can be differentiated by collating the model compounds according to the logarithmic plots of their mass spectral abundance ratios as a function of the collision energy.
著者
雨宮 正欣 長井 辰男
出版者
日本法科学技術学会
雑誌
日本鑑識科学技術学会誌 (ISSN:13428713)
巻号頁・発行日
vol.4, no.2, pp.95-98, 2000 (Released:2010-02-05)
参考文献数
14
被引用文献数
1 1

Though easiness and availability of a screening test are important factors, its correctness is most important for a drug abuser's arrest according to screening results. The use of Triage® in screening tests to detect stimulants was examined.   Abusers' urine samples contained methamphetamine at the concentration of which ranges from 1μg/ml to 479 μg/ml, and 66 μg/ml(n=68) on the average. Triage® showed negative reaction at 1000 μg/ml to 1500 μg/ml, even though there was a high concentration of methamphetamine. Triage® gives false negative result, even when there is a very high concentration of stimulant present in the urine. We should take this into consideration.
著者
宮田 瞳 市川 啓子
出版者
日本法科学技術学会
雑誌
日本法科学技術学会誌 (ISSN:18801323)
巻号頁・発行日
vol.12, no.1, pp.61-72, 2007 (Released:2007-06-27)
参考文献数
18

In an examination of sexual crime cases, the possibility that constituent fibers of the top sheet of a sanitary napkin or a panty liner, which the victim may have been using, might stick to the suspect's hands and fingers were examined.   Nineteen brands of sanitary products (15 sanitary napkin brands and 4 panty liner brands) were classified, by their material of the top sheet, in 12 brands of non-woven fabrics and 7 brands of porous films. The 12 brands of non-woven fabrics products were classified by their bonding process in 2 types, i.e. thermal bonding (through-air oven bonding) and mechanical bonding. Meanwhile out of 19 brands of products, 9 products have non-woven fabrics on both sides of the top sheet to prevent leakage and all of their bonding processes are thermal bonding (point-bond hot calendaring).   Next, materials stuck to two subjects' fingers were collected on a transparent adhesive tape and examined whether constituent fibers came off and stuck to their fingers when two subjects rubbed the surface of a sample with their fingers. It was found that constituent fibers of non-woven fabrics stuck to the transparent adhesive tape.   As a result, it was found that constituent fibers of non-fabrics came off by rubbing and stuck to fingers and hands, though those of porous films did not stick to them. Consequently, it is suggested that examination of constituent fibers of sanitary products is noteworthy for sexual crime cases.
著者
小野 孝明 友成 航平 森 名生 冨阪 吉登 西 英二
出版者
日本法科学技術学会
雑誌
日本法科学技術学会誌 (ISSN:18801323)
巻号頁・発行日
vol.20, no.1, pp.69-81, 2015 (Released:2015-02-10)
参考文献数
18
被引用文献数
1

Accurate DNA quantification is required for the short tandem repeat typing of forensic samples. Various commercial DNA quantification kits for forensic DNA analysis have recently been released. However, DNA quantification may fail if too much PCR inhibitor is extracted with the target DNA sample. Therefore, this study experimentally evaluated the degree of the alteration of DNA quantification results of various commercial DNA quantification kits (Takara RR281, Quantifiler Duo DNA Quantification Kit, Plexor HY System, Investigator Quantiplex HYres Kit, Quantifiler Trio DNA Quantification Kit, and Quant-iT dsDNA HS Assay Kit) in the presence of various concentrations of PCR inhibitors such as hematin, humic acid, indigo carmine, melanin, and tannic acid. Compared to the other kits, the DNA quantification abilities of the Investigator Quantiplex HYres Kit and Quant-iT dsDNA HS Assay Kit were not negatively affected by high concentrations of hematin. The DNA quantification abilities of the Quantifiler Trio DNA Quantification Kit and Quant-iT dsDNA HS Assay Kit were not negatively affected by high concentrations of PCR inhibitors containing humic acid, indigo carmine, or melanin. The DNA quantification abilities of the Investigator Quantiplex HYres Kit and Quantifiler Trio DNA Quantification Kit were not negatively affected by high concentrations of tannic acid. Furthermore, the DNA quantification ability of the Quantifiler Trio DNA Quantification Kit was more reproducible than those of the other kits. Moreover, this kit was able to assess the degree of DNA degradation by comparing quantified both the short amplicon (80 bp) and long amplicon (130 bp). However, the short amplicon was not negatively affected by high concentrations of PCR inhibitors in contrast to the long amplicon. These results indicate forensic DNA analysts should select the appropriate DNA quantification kits that are unaffected by PCR inhibitors and carefully interpret DNA quantification results.
著者
勝又 義直
出版者
日本法科学技術学会
雑誌
日本法科学技術学会誌 (ISSN:18801323)
巻号頁・発行日
vol.13, no.1, pp.1-6, 2008 (Released:2008-04-19)
参考文献数
5
被引用文献数
3

The importance of scientific evidence in criminal investigation is now increasing, and more and more novel techniques are introduced in forensic science field. So, the court has great difficulty in determining the admissibility of scientific evidence. The situation will get worse after when a big reform of the court will begin in 2009 because citizens not being trained for the judicial judgment will participate in the court. In order to solve this problem the efforts of the court and forensic scientists are needed.
著者
財津 亘
出版者
日本法科学技術学会
雑誌
日本法科学技術学会誌 (ISSN:18801323)
巻号頁・発行日
vol.15, no.2, pp.111-124, 2010 (Released:2010-08-27)
参考文献数
23
被引用文献数
1 1

Serial arsonists (N=125) were differentiated into four groups on the basis of their social independence and the degree of criminality, by using categorical principal components analysis (CATPCA). Results indicated the following. (1) Arsonists with high social independence and high criminality were aged 40 years or more in age, did not live with their parents, and tended to have criminal records for theft. (2) Arsonists with high social independence and low criminality were most frequently employed, high school graduates, married, and had no criminal record. Moreover, there were more female and mental patients in this group compared with other groups. (3) Arsonists with low social independence and high criminality were all male, compulsory education level (including high school dropouts), unmarried, not living with parent(s), and had no criminal record of theft. These arsonists tended to have relatively no criminal record of arson compared with other groups. (4) Arsonists with low social independence and low criminality were the youngest among four groups and were aged between 10 and 30 years, unmarried, lived with their parent(s), and had no criminal record. Results of log-linear analysis indicated that arsonists with high social independence tended to use a car or walk to the crime scene, whereas those with low social independence were inclined to use a bicycle. Moreover, arsonists with high criminality records tended to prepare the medium for arson in advance and drink alcohol before the offence, whereas arsonists with low criminality had a tendency to set fire to the same place repeatedly.
著者
肥田 宗政 伊藤 健次郎 三井 利幸
出版者
日本法科学技術学会
雑誌
日本法科学技術学会誌 (ISSN:18801323)
巻号頁・発行日
vol.11, no.2, pp.185-191, 2006 (Released:2007-01-19)
参考文献数
3

A mixed solution of 28% of ammonia and pyridine (9 : 1 (v/v)) was used to extract dye ink from counterfeit paper money printed by an ink-jet printer. The counterfeit paper money was fixed on a vacuum filtration device instead of a membrane filter. The extracted solution was collected in a test tube and was evaporated to dryness under reduced pressure in a 40°C water bath. The extract was dissolved by 10 μl of the extraction solution and spotted on a silica gel plate. The silica gel plate was developed by iso-propanol : 28% ammonia : pyridine (2 : 9 : 1 v/v/v). By comparison with TLC patterns, we could clearly distinguish among the various printer companies. Furthermore the TLC pattern was discriminated between the machine types to some extent.
著者
戸根 康隆 相澤 優秀 西川 悟 耒代 誠仁
出版者
日本法科学技術学会
雑誌
日本法科学技術学会誌 (ISSN:18801323)
巻号頁・発行日
vol.22, no.2, pp.145-151, 2017

&emsp;In criminal investigations, writer-identification to discriminate writers of documents used in crimes has important roles. In the identification processes, writer-unknown documents are compared with writer-known documents. Experts of the process give careful considerations for the comparisons by referring to handwriting-samples, experimental-data, and other vast knowledge collected from past investigations. Characteristics of handwritten strokes written on the documents are highly useful for the experts. Therefore, accurate and efficient managements of the characteristics are important. However, in the daily investigations, the characteristics have been recorded in a huge amount of paper media without indexes, and the amount is growing. In this paper, we propose two prototypes of database system to store and retrieve the characteristics. The database system consists of (1) common digital formats to indicate the characteristics, (2) aggregation functions of the digital indicators for the retrieval, and (3) user interface for the experts. The first prototype is implemented with VBA of Microsoft Excel. We present our experimental results by using 228 testing data sets. The second practical prototype is implemented with XML and Java. We expect that our database system will improve the efficiency and the accuracy of the writer-identification processes, and accelerate information sharing among the experts beyond time and space.<br>
著者
原 忠嗣
出版者
日本法科学技術学会
雑誌
日本鑑識科学技術学会誌 (ISSN:13428713)
巻号頁・発行日
vol.9, no.1, pp.59-63, 2004 (Released:2007-12-05)
参考文献数
2

At present, the footprint identification is conducted by the number of distinguishing characteristics point in the footprint. Life size footprints photos were usually used and magnified footprints photos were seldom used.   If these characteristics parts were magnified and showed minute distinguishing marks more evidential values could be added to them.   The method developed in this paper was to take pictures of magnified characteristic parts of both footprints retrieved at a crime scene and ones taken from shoes themselves in the same magnifying power, followed by enlarging photos from the negatives and comparing the minute distinguishing marks by superimposition.   This method enables us to make magnified footprints photos of about 5 to 30 magnifications easily in a short time.   By inspecting the magnified footprint photos, it was proved that one part which was simply evaluated as one characteristic in the present method actually had many distinguishing marks.
著者
乗峯 絵理 宮田 勝文 石澤 不二雄 鷹巣 正則 本田 克也
出版者
日本法科学技術学会
雑誌
日本法科学技術学会誌 (ISSN:18801323)
巻号頁・発行日
vol.18, no.1, pp.65-70, 2013 (Released:2013-02-20)
参考文献数
11

The authors have reported 4 successfully-detected cases of helium in postmortem blood by headspace-gas chromatography (HS-GC). Postmortem blood was collected into a depressurized 4-ml glass vial to prevent volatilization loss of helium. MICROPACKED-ST column (2.0 m×1.0 mm i.d., 80/100 mesh) was used as a separation column, and thermal conductivity detector was selected as a gas chromatographic detector. Argon was used as a carrier gas, and the flow rate was set at 8.3 ml/min. After 0.5 ml air was released into the vial, 0.5 ml headspace gas was manually injected to the instrument. In this analytical condition, helium was well-separated from other gases in the atmosphere. This HS-GC method was applied to real blood samples of 4 suspected cases of helium inhalation, resulting in successful detection of helium in blood in all cases.   In the case of a suicide by helium inhalation, it is generally difficult to determine the cause of death from an autopsy finding. This case report provides a practical method to obtain direct proof of helium inhalation.
著者
財津 亘 金 明哲
出版者
日本法科学技術学会
雑誌
日本法科学技術学会誌
巻号頁・発行日
2017

&emsp;Author identification through text-mining aims to judge whether an author suspected of writing a certain text is same as that of control texts. This study examined the validity of scoring for author identification. In one unit of analysis, we conducted 18 analyses (six writing styles×three multivariate analyses) across one suspected text of a blogger, one control text of a blogger, and irrelevant texts of four bloggers. The writing style factors were (1) rate of usage of non-independent words, (2) bigram of parts-of-speech, (3) bigram of postpositional particles, (4) positioning of commas, (5) rate of usage of Kanji, Hiragana <i>et al.</i>, and (6) sentence length. We completed (1) principal components analysis, (2) corresponding analysis, and (3) multi-dimensional scaling. We obtained scores from arrangements of texts on two dimensions, convex hull polygon (CHP) consisting of control texts was overlapped with that of irrelevant texts (a score of 0). Besides not overlapping each CHP of control and irrelevant texts, (a score of +2) a suspected text arranged into CHP of control texts, (a score of +1) one not arranged into CHP of control texts but near a control text, and (a score of &minus;1) one near an irrelevant text. We totaled the scores in one unit of analysis (18 results) and analyzed the total scores of the 240 units of analysis for 10 bloggers under the following design: 2 (author combination of suspected and control texts: same, different)×4 (number of characters: 250, 500, 1000, 1500)×3 (number of control and irrelevant texts: 3, 6, 9). The results indicated the scoring method was able to identify the authors. AUCs of number of characters were statistically significant, but the number of texts was not significant. Furthermore, rate of usage of non-independent words and parts-of-speech were quite useful to identify authors.<br>
著者
太田 奈穂樹 岩本 良二 相場 伸 村川 雄大 棟方 栄治 川口 龍一
出版者
日本法科学技術学会
雑誌
日本鑑識科学技術学会誌 (ISSN:13428713)
巻号頁・発行日
vol.9, no.2, pp.95-102, 2004 (Released:2007-11-07)
参考文献数
8

In a recent murder case, many feathers were left at the crime scene and collected for analysis. It seemed they were likely left from the suspect's torn jacket. Goose and duck downs are commonly used for clothes and bedclothes, especially in high quality goods where goose feathers are used most often. Unfortunately, at the time of the murder there were few studies in Japan about down identification. This paper presents how to identify goose and duck downs by microscopy.   Ten downs were removed at random from each stuffed bird from sixty-one species at the prefectural museum. Ten downs were removed at random from ten geese and ten ducks, respectively, at the prefectural farm. Therefore, the authentic sample set (family or species known) included ten downs each from eighty-one birds, representing sixty-three species. In addition, two hundred goose downs and two hundred duck downs were obtained from samples supplied by the Japan Spinners Inspecting Foundation in Tokyo.   These down samples were examined microscopically with respect to eight morphological characteristics: full length, color, node shape, maximum node width, maximum node interval, node distribution, node density (number of nodes per mm) and pigment distribution. Morphological data from geese were compared with ducks and analyzed statistically using F-test.   Duck and goose downs are identified primarily by their triangular nodes. In birds of the sixty-three species other than those from the duck and geese species, triangular nodes were found only in the Anatidae, Columbidae and Psittacidae families. Fortunately, it was quite simple to distinguish the families by the node distribution along the shaft of the barbules. For example, the Anatidae family has triangular nodes only toward the tip of the barbule, the Columbidae family has them mainly toward the base of the barbule, and the Psittacidae family has them uniformly distributed along the shaft of the barbule. Based on feather nodes, both goose and duck can be placed in the Anatidae family. Nevertheless, they can be distinguished. Goose has wider maximum node intervals than the duck, usually more than fifty-five micrometers. On the other hand, duck has higher node density than the goose, more than sixteen per mm. Statistical analysis using the F-test showed that the maximum node interval and node density were useful characteristics for distinguishing a goose from a duck down.