著者

志摩 典明 片木 宗弘

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.26, no.2, pp.137-157, 2021 (Released:2021-07-31)

参考文献数

65

---

Increasing numbers of drug-facilitated sexual assaults (DFSAs) have been reported recently and have become a social concern. In DFSAs, biological specimens (urine, blood, and hair) are analyzed to prove the victim's drug exposure, which can lead to proof of the sexual crime. Hair is the only specimen that can provide firm evidence of drug ingestion in cases of long delays (more than a week) in reporting the crime. Furthermore, detailed sectional hair analysis of a single hair strand enables to estimate the victim's drug-use history (date and amount of intake). Several recent studies have demonstrated high-sensitivity methods using mass spectrometry to detect sub-pg/mg concentrations of hypnotics in hair, and additionally illustrated the incorporation pathways of drugs and detailed distribution patterns in the hair after intake. Based on these findings, hair testing for hypnotics has been put to practical applications since 2016. In this paper, we review the practical concepts and usefulness of hair testing for hypnotics while introducing the current situation of DFSAs.

著者

山室 匡史 岡田 侑己 瀬川 尋貴 桑山 健次 辻川 健治 金森 達之 岩田 祐子

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.27, no.1, pp.73-83, 2022 (Released:2022-01-31)

参考文献数

11

被引用文献数

1

---

In Japan, possession of germinable cannabis seeds for cultivation purposes is subject to prosecution. Cannabis seeds are marketed after being treated to prevent germination (heated or crushed). Currently, forensic examination of cannabis seeds is conducted by cultivating the seeds after germination tests for several weeks and then performing morphological observation and chemical analysis on the true leaves. In this study, we attempted to construct a rapid and simple method for the identification of cannabis seeds by combining the color reaction using 2,3,5-Triphenyl-2H-tetrazolium Chloride (TTC), a reagent that discriminates between living and dead cells, and DNA testing using a commercially available simple kit. The color reaction using TTC can determine the viability of peeled embryos within 20 min at 45 ℃ as previously reported. This method is effective for quickly determining whether a seed has been heat-treated or not. However, in the color reaction, a commercial health food seed that claimed to be unheated showed some coloration. This sample had been crushed to prevent germination and was easily identified as non-germinable by morphological examination. After the color reaction, the embryos could be directly used for DNA extraction without washing, and the DNA testing could be carried out in about 2 hours by following the instruction manual of the kit. By following the above procedure, it was possible to identify in one day whether a seed was a germinable cannabis or not, without the need to cultivate the plant. This method is expected to make a significant contribution to improving the efficiency of cannabis seed analysis.

著者

鎌田 徹 片木 宗弘 中西 啓子 財津 桂 志摩 典明 鎌田 寛恵 三木 昭宏 土橋 均

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.1, pp.15-23, 2010 (Released:2010-02-27)

参考文献数

18

被引用文献数

3 3

---

The metabolism and urinary excretion of N-hydroxy-3,4-methylenedioxymethamphetamine (N-OH MDMA), a newly banned narcotic in Japan, were explored to confirm biotransformation of N-OH MDMA to 3,4-methylenedioxymethamphetamine (MDMA) and to discriminate between N-OH MDMA and MDMA intake in forensic urine analysis. The in vitro and the in vivo experiences were performed with human liver S9 and rats, respectively, and the resultant products or metabolites were determined using liquid chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry.   In both the in vitro and the in vivo experiences, MDMA and 3,4-methylenedioxyamphetamine (MDA) were detected, and the MDA levels exceeded the MDMA levels throughout the entire periods except for during 3 h after administration to the rats. This suggests the existence of the metabolic pathway(s) from N-OH MDMA to MDA not via MDMA. In urine samples from the administered rats parent N-OH MDMA and its demethylated metabolite N-hydroxy-3,4-methylenedioxyamphetamine (N-OH MDA) with very low levels during short period after administration (≤6 h) were detected. The ratios of the urinary MDA/MDMA levels for N-OH MDMA-administered rats were higher than those for MDMA-administered rats. In addition, the determination of urinary diastereomers of glucuronidated 4-hydroxy-3-methoxymethamphetamine (HMMA), MDMA metabolite, revealed that the relative peak intensity of l-HMMA-glucuronide to d-HMMA-glucuronide was higher in the case of N-OH MDMA-administration than in the case of MDMA-administration.   Detection of MDMA in both the in vitro and the in vivo experiences suggests that N-OH MDMA intake will result in MDMA excretion also in human urine. To discriminate between N-OH MDMA and MDMA intake the following view points would be applicable in urine analysis: 1) detection of N-OH MDMA and/or N-OH MDA, 2) MDA/MDMA ratio, and 3) peak intensities of diastereomeric HMMA-glucuronides.

著者

木下 勝博

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.6, no.2, pp.65-83, 2002 (Released:2009-10-14)

参考文献数

101

被引用文献数

1 1

---

Tracking phenomenon, to put it plainly, is the phenomenon to form the carbonized electrical track and lose insulation in the part with potential difference on the surface of insulating materials. Tracking resistance means the difficulty occuring the tracking phenomenon of the organic insulation materials. Studies on the tracking phenomenon and the method of evaluating tracking resistance has been often reported on so far. But, there are only a few comprehensive researches and commentaries which include tracking phenomenon and the fire which occurs by the tracking phenomenon. Hence, I decided to explain tracking phenomenon of the organic insulating materials and the phenomenon that developed concerning the fire which develops and is called, tracking fire. Tracking phenomenon is discussed first. Next, cases of tracking fire in electric wiring and the wiring utensil and the studies on the cause of tracking fire are explained. Furthermore, prevention of tracking fire and future problems are also discussed.

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

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

vol.20, no.1, pp.1-14, 2015 (Released:2015-02-10)

参考文献数

28

被引用文献数

5

---

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

小川 時洋 松田 いづみ 常岡 充子

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.18, no.1, pp.35-44, 2013 (Released:2013-02-20)

参考文献数

20

被引用文献数

10 12

---

Currently, polygraph examinations in Japan use the concealed information test (CIT) to determine whether a suspect knows specific details of a crime. The present study examined the accuracy of the CIT as a memory detection technique in a mock-theft experiment. Participants were randomly assigned to either an encoding or non-encoding group. An expert polygrapher who was not informed of the group assignments, conducted a CIT that consisted of two questions. One inquired about a card number chosen by the participant, and the other regarded an item that had been stolen. Analyses focused on the second question. Roughly 20% of cases were judged inconclusive while sensitivity and specificity for the remaining cases were 86% and 95%, respectively. Analysis was repeated using modified Lykken scoring, and rates of inconclusive cases, sensitivity, and specificity by this method were 25%, 83%, and 91%, respectively.

著者

岩本 良二 太田 奈穂樹 相場 伸 村川 雄大 棟方 栄治

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.6, no.2, pp.99-108, 2002 (Released:2009-10-14)

参考文献数

24

---

This paper presents a study of the intra-individual variation of pubic hairs. Seventy pubic hairs were pulled from seven sites around the outer genital area of each of five Japanese males; sixty were obtained from six sites on each of four Japanese females, and fifty from six sites on one additional Japanese female. These hairs were examined with respect to twenty-two morphological characteristics. These morphological data were studied in relation to each site and analyzed by the statistical method of cluster analysis.   It appeared that a pubic hair's length, luster, diameter, medullary index, disease and scale damage bore some relation to the site from which it was obtained. Dendrograms produced through the cluster analysis showed a hierarchy of similarities among all pairs of pubic hairs. Similar hairs were placed together into several large or small groups within the same person. Some groups contained pubic hairs from many sites, whereas others were almost exclusively from only one site. This means that some sites have different characteristics from other sites. Pubic hairs obtained from the penis area, scrotum and labium majus area showed greater dissimilarity than other sites within the same person.   Therefore, in forensic hair comparison, known pubic hair samples should be obtained from many different sites. For males, at least thirty-five pubic hairs should be collected from seven sites (center, left and right abdomen; upper, left and right area surrounding the penis; and scrotum). For females, at least thirty pubic hairs should be collected from six sites (center, left and right abdomen; mons pubis; left and right labium majus).

著者

浅井 龍太郎 鎌田 徹 新田 篤志 和田 美暁 掛橋 秀直 中野 史保子 松田 駿太朗 志摩 典明 西岡 裕 三木 昭宏 片木 宗弘

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.24, no.1, pp.43-48, 2019 (Released:2019-01-31)

参考文献数

18

---

In order to expose substituted, cheated and faked urine specimens submitted for a drug test, a simple and highly sensitive screening method has been developed for the detection of urea in the specimens. This method uses the coloration of a piece of pH test paper which is wetted and set into the headspace of a sample vial containing “urine”, by absorbing NH3 gas generated by the urease reaction. The present method named, “Urease-Headspace method” (UHS method), was evaluated by applying it to various diluted or adulterated urine samples. The detection limit of urea in water was 2×10−4%, which was 100 times higher sensitivity compared with a conventional p-(dimethylamino)cinnamaldehyde (DAC) test. The UHS method was applicable even to deeply colored specimens such as bloody urine because the coloration occurs in the headspace of the sample vial. The UHS method quickly revealed the substituted specimens, e.g. water and green tea. Thus, the present UHS method will be effective for the validity determination of urine specimens, which is increasingly crucial in forensic drug examination.

著者

平川 俊介 案部 雄一郎 山下 珠希 内野 隆一郎 丸田 英基 才本 明秀 石松 隆和

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.125-140, 2015 (Released:2015-07-17)

参考文献数

15

---

Handgun bullets fired toward the windshield of an automobile sometimes ricochets. In such a case, we must estimate the type of bullet and direction of shooting from the damaged windshield. The purpose of this study is to obtain a method to estimate the fired direction of a handgun bullet from the fractured windshield. We test fired bullets to an automobile windshield with various incidence angles. The thickness of the windshield is slightly different from model to model of the automobiles. In the beginning, we examined the strength of the automobile windshield of various car models. First, we examined the static failure strength of the windshield by an indentation test. In this test, fracture load and the amount of indentation were measured on windshield samples cut from ten models of Japanese automobiles. Next, we test fired a handgun in order to examine the relation between the trajectory of a bullet and the collision marks on the windshield. The cartridges used in these test firings were 38SPL. lead round nose (LRN) bullet and full metal cased (FMC) bullet. In the results of static indentation test for different car models, there was found to be almost no differences in the relationship between fracture load and indentation depth. With the LRN bullet, bullets perforated the windshield when the incidence angle was less than 45 degrees and ricocheted when the incidence angle was greater than 60 degrees. In these cases, a characteristic damage was left on the windshield. On the other hand, FMC bullets of 38SPL. perforated the windshield when the incidence angle was less than 60 degrees and ricocheted when the incidence angle was greater than 70 degrees. Based on these results, we proposed a method to estimate the direction of shooting in criminal cases in which a bullet was fired on an automobile windshield.

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

4

---

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

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

5

---

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 3

---

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

森好 浩行 三好 美紀 日野 大樹 中山 英樹 森川 俊雄 中木 真一 糸原 幸次

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.14, no.2, pp.61-70, 2009 (Released:2009-08-25)

参考文献数

19

被引用文献数

6 7

---

Facial image identification has become important in forensic science because surveillance cameras are popularly used as silent witnesses at potential crime scenes. In general, three methods are used for facial image identification: morphological comparison of facial features, facial image anthropometry and face-to-face superimposition. The most commonly employed method in actual casework is morphological comparison based on the morphological classification of facial components such as facial types, eyebrows, eyes, nose, lips and ears. However, classification for ear morphology has not been developed, except for the ear lobe. The human ear has various anatomical parts, including the helix, antihelix, tragus, antitragus, scaphoid fossa, and ear lobe. The present study was designed to develop a new classification system for the ear.   Ear images obtained from 164 Japanese adult males (n=94, age range: 24-60) and females (n=70, age range: 20-54) were used for establishing the morphological classification. In general, the features of the ear are very easily influenced by camera angle, which usually make it difficult to compare facial images taken with surveillance cameras to mug shots in actual casework. In our previous study, however, it was suggested that some components of the ear are little affected by camera angles if the scaphoid fossa could be found on the image even though the external acoustic meatus could not be found. Therefore, the morphological characteristics of some components such as the antihelix, tragus, antitragus, scaphoid fossa, and ear lobe were observed in the ear images from all persons, and morphological classification items for those components were established. All data classified according to these items were analyzed to obtain their frequency distribution in each component and to clarify the correlation between morphological characteristics. The results revealed that some morphological characteristics in each component were significantly correlated.   The present classification system for ear morphology would be useful for facial image identification.

著者

大塚 麻衣 山口 晃巨 数井 優子 西田 響 大森 毅 宮口 一

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.28, no.2, pp.169-176, 2023 (Released:2023-07-31)

参考文献数

14

---

Cyanide is a gaseous poison which is liberated from cyanide compounds such as potassium cyanide. In spite of high toxicity, cyanide compounds are easily accessible for industrial use, and some contamination cases of cyanide into beverages have occurred. For analysis of cyanide, various analytical methods such as colorimetric methods have been reported. Among those, headspace-gas chromatography-nitrogen phosphorus detection (HS-GC-NPD) is known for its easy pretreatment method and high quantitation ability. The application of HS-GC-NPD analysis to cyanide in blood specimens have been reported by many groups. However, comparison results of some experimental manipulations, such as addition of acid, syringes used for introduction of samples to the GC, and amount of sample introduced into the GC are not clear. In addition, there is no detailed description about application to beverage samples. In this work, we have investigated some experimental manipulation of manual HS-GC-NPD and applied the optimized method to beverage samples. After the optimization, the addition of acid with micropipette in open system and introduction of 100 μL of headspace gas into GC with gastight syringe are recommended. For beverage samples, although variations were larger than standard samples, those variations could be compensated by use of acetonitrile as an internal standard.

著者

工藤 雅孝 風間 守 阿部 積

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.14, no.2, pp.93-98, 2009 (Released:2009-08-25)

参考文献数

8

被引用文献数

1 1

---

The blast wave caused by the explosion of the explosive and so on shows the refractive index which is different from that of ambience because the wave is accompanied by the density change of the medium. The Schlieren method is often used as a technique to observe the behavior of fluid using the difference of refractive index. However, it is difficult to apply to outdoor experiments because the method requires arrangements of some optical equipments around the subject. In this study, the visualization of the blast wave in a convenient method from the digital frame images which had been taken by a digital high-speed camera in a past outdoor experiment without any optical equipment was tested. This method was a subtraction of images, and a processed image was produced by difference of gradations between two original frame images before and after the explosion. In a part of the background which resulted in a mottled pattern having minute bright and dark parts, the blast wave was possible to be visualized in every frame image. The main blast wave and reflected blast wave from the ground were observed in the processed images. The equivalent ratio to other conventional explosives was derived from the propagation of the blast wave clarified by the processed images. Consequently, this method can be used for estimation of the power of explosion.

著者

金森 達之 桑山 健次 辻川 健治 宮口 一 岩田 祐子 井上 博之 岸 徹

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.237-245, 2007 (Released:2007-10-06)

参考文献数

7

被引用文献数

3 4

---

A urine sample obtained from a phenothiazine user was examined to identify metabolites which caused false-positive result on a screening test for methamphetamine in urine based on the Simon's color test. The urine sample was processed by liquid-liquid extraction under mild alkaline condition, and the extract was analyzed by TLC using Simon's reagent as a visualization reagent. Two blue or violet spots were appeared on the TLC plate by this reagent, and were identified as norchlorpromazine sulfoxide and norpromethazine sulfoxide by mass spectrometry after purification of the spots. Both of these two compounds possess an aliphatic secondary amine moiety, and are known as the metabolites of chlorpromazine and promethazine. These metabolites in the above urine sample were also confirmed by HPLC and LC/MS analysis. A control urine sample spiked with these metabolites gave positive result on the above screening test, indicating that these metabolites were the substances which caused false-positive on the test.

著者

廣田 昭久 横田 賀英子 和田 純一郎 渡辺 昭一 高澤 則美

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.5, no.1, pp.33-53, 2000 (Released:2009-11-27)

参考文献数

81

被引用文献数

9 7

---

In the present study we investigated heart rate and heart rate variability (HRV) in the guilty knowledge test (GKT). Participants were instructed to “steal” envelopes and hide them. Participants were then presented with questions focusing on certain aspects of the particular envelopes they had stolen. They were requested to respond with “no” to every question, thus denying their knowledge about the critical items. Heart rate, SCR, and HRV components of high-frequency (HF) and low-frequency (LF) were measured during the GKT examinations. Results showed that heart rate decreased in the critical items. They also showed that decrement of heart rate was most distinctive about 10-15 seconds after the onset of the questioning of the critical items. The results indicated that there is a characteristic response pattern between heart rate and HRV concerning the critical items. That is, heart rate decrement is accompanied by increment of HF component and decrement of LF component. Also, in order to examine which method would serve as the most effective measure for psychophysiological detection of deception, we compared among three different analytical methods: fast Fourier transform (FFT) analysis, peak-to-valley method, and complex demodulation (CDM) method, in assessing HRV, respectively. Results showed that the CDM method traced both HF and LF amplitudes were most effectively, and therefore would be the best indices for detection. Some hypotheses were discussed concerning psychophysiological responses in detection of deception, one of which was the implication that subjects might have adopted passive coping, in other words, hemodynamic reaction pattern-II, when presented with the critical items, because of the particular cardiovascular response pattern shown in the psychophysiological detection of deception.

著者

井元 大輔 黒沢 健至 土屋 兼一 黒木 健郎 平林 学人 秋葉 教充 角田 英俊

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.24, no.1, pp.23-41, 2019 (Released:2019-01-31)

参考文献数

17

---

Gait recognition is one of recently evolving techniques by which we can recognize individuals by one's gait. There are two major approaches; silhouette-based and model-based. In Japan, a method based on GEI (Gait Energy Image), which is one of the silhouette-based approaches, is used for forensic purposes. Sometimes, it is a problem of silhouettes' variabilities in one person due to different clothing that lessen recognition reliability under the GEI method. Here, we analyzed and evaluated the average error rates under clothing variation conditions using the method called Dynamic-features method, which we previously proposed. The Dynamic-features method was built inspired by previous studies of model-based gait recognition, which uses time-series of feature points and local shape features around the points automatically extracted from silhouette sequences. Before analysis, we roughly categorize whole data in the OU-ISIR gait database -treadmill dataset B-, which contains side-view data, into five clothing categories in order to deal with realistic off-line forensic situation, where we cannot strictly control the clothing conditions. As a result, the average increases of average error rate of GEI-based methods due to different clothing were ranged from approximately 8 to 11%, whereas that of the Dynamic-features method was approximately 3%. It was found that two representative dynamics of a feature point of one same person, where the point is influenced by different clothing conditions, showed different mean values but showed similar trends. Based on this fact, it is suggested that robustness of performances in Dynamic-features method under clothing variation conditions is obtained by effective utilization of dynamic properties of human's gait.