• Convergence Security Journal
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• v.15 no.1
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• pp.49-57
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• 2015

As the capitalist society was launched, false has been increasing day by day for the personal profit. Study after study since a long time ago has concluded that today's polygraph developed in order to determine these false. In Korea the polygraph has been used actively in current investigation agency, and passively in a private enterprise by a former polygraph examinant from the investigation agency. Each investigation agency is recruiting polygraph examinants through the strict qualifications, training education. Decisions of Supreme Court precedents about the polygraph test results are denying admissibility of evidence in reliability on the efficiency of a test equipment, way to ask, qualities of polygraph examinant, etc. The most fundamental cause of the issues mentioned in the precedents is that examinants of each investigation agency are being trained by dual education not centralized. Because of each investigation agency has its own training and polygraph examinant, each agency can occur variations every agency or every examinant, therefore ensuring the centralized educational system is needed. In this way, ensuring the centralized educational system will contribute to improve the reliability of polygraph test results and make a retrenchment in the educational budget in accordance with examinant training of each agency.

• Korean Journal of Culture and Social Issue
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• v.14 no.4
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• pp.1-18
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• 2008

The present study examined the accuracy of polygraph tests through two types of statistical methods with unknown ground truth. One method evaluated the accuracy based on the rates of agreements between polygraph test results of crime suspects and prosecutors' indictment decisions for them. Those crime suspects were tested with polygraph by the Prosecutors' Office of the Republic of Korea between 2000 and 2004. The other method estimated the accuracy by using the latent class analysis based on the frequency distributions of the polygraph results and indictments during 2006. Excluding cases that were 'inconclusive' on the polygraph test, the study showed that the accuracy of the polygraph tests is .914 (SE=.004) for the 2000-2004 data, and .885 (SE=.021) for the 2006 data. With the inclusion of 'inconclusive' cases in the 2006 data, the results from the latent class analysis showed the accuracy in the range between .707 and .734 (SE=.027~.031), with false positives between .078 and .087 (SE=.019~.023), and false negatives between .029 and .078 (SE=.010~.023). The probability that the polygraph test correctly classifies subjects appeared to be in the range between .912 and .925 (SE=.013-.016) for those who lie, and in the range between .867 to .955 (SE=.011-.040) for those who tell the truth.

• Korean Journal of Culture and Social Issue
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• v.14 no.4
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• pp.103-117
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• 2008

The polygraph test administered by the Korean Prosecutors Office for crime investigations customarily uses the score of -12 as the cutoff point separating the subjects who lie from those who tell the truth. The criterion used by the KPO is different from the one (-13) suggested by Backster (1963) who invented the particular method for lie detection. Based on the signal detection theory applied to the real polygraph test data obtained from real crime suspects by the KPO, the present study identified the score of -8 as an optimal criterion resulting in the highest overall accuracy of the polygraph test. The classification of the subjects with the score of -8 as the criterion resulted in the highest accuracy (83.17%) compared with the accuracies of classifications with the Backster's criterion (76.24%) and the KPO's criterion (80.20%). However, the new criterion was also found to result in more false-positive cases. Based on the results from the present study, it was recommended to use the score of -8 as the criterion when the overall accuracy is important but the score of -12 or -13 when avoiding false-positive is more important than securing the overall accuracy.

• Science of Emotion and Sensibility
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• v.11 no.4
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• pp.553-564
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• 2008

Generalizability theory was employed to examine how the reliability of polygraph test is affected by the number of relevant questions, the number of repeated tests (the number of of charts), and the number of raters(scorers). The data consisted of the results of the polygraph tests administered to 31 crime suspects. The sample was drawn from the real polygraph tests based on Backster ZCT and archived by the Prosecutor's Office of the Republic of Korea. The numerical scores assigned by thirteen raters to the test charts were analyzed to determine the generalizability of the scores. The largest variance component was accounted for by the examinee factor(43.97%) and the residual variance component was 16.84% of the total variance. The variance component due to the interaction between the examinee and the chart factors was 12.17% and the variance component due to the three way interaction of the examinee, the repeated test, and the relevant question factors was 10.31%. The generalizability coefficient for the current measurement procedure as practiced by the Korean Prosecutor's Office was 0.74 which suggests that the current procedure is acceptable. However, measurement procedures with the combination of more than two relevant questions, more than three repeated tests, and more than two raters were generally found to yield generalizability coefficients larger than 0.80. Therefore, such procedures need to be considered seriously in order to significantly improve the reliability of polygraph test.

• Science of Emotion and Sensibility
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• v.12 no.4
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• pp.557-564
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• 2009

For scoring polygraph charts, the Prosecutors' Office of the Republic of Korea uses a consistency criterion in which an elevated signal on one physiological channel is scored as a deceptive response only if the signal is also elevated on other channels. In the current study, the effects of this scoring criterion on reliability and accuracy (validity) of polygraph scores were assessed. Polygraph tests on 26 suspects were evaluated twice by the same examiners. The examiners used the consistency criterion in the first evaluation. In the second evaluation, the examiners were prevented from using the criterion; the signals from each physiological channel were separated and randomly arranged before they were rescored by the same examiner. Reliability was assessed by the variation among the scores for each suspect. Accuracy was assessed by establishing a standard, based on a Latent Class Analysis model, using the results of polygraph tests on each of 182 additional suspects. Reliability and accuracy were both improved by the use of the consistency criterion which therefore was recommended.

• Korean Journal of Forensic Psychology
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• v.12 no.1
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• pp.53-73
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• 2021

This study is an experimental study comparing the psycho-physiological response differences of subjects according to the rapport building in polygraph tests. We randomly assigned 84 adults into a 2(veracity: Truth vs. Lie) x 2(rapport; Rapport building vs. Non-rapport building) between-subject design and measured ESS total scores as psycho-physiological responses. In order to manipulate the veracity conditions, participants in the truthful condition were told to tell their actual scores on several simple tasks but those in the lie condition were asked to tell higher scores than their actual scores. Afterwards all participants were polygraph tested in the order of pre-interview and main examination. The rapport conditions were manipulated by structured pre-interview scripts. As a result, there were significant differences in the examinee's total ESS scores depending on the veracity and rapport conditions. For truth-tellers, the ESS total scores were greater in the positive(+) direction in the rapport building condition than in the non-rapport building condition, indicating a prominent true response in the former condition. For liars, however, the ESS total scores were not significantly greater in the negative(-) direction in the rapport building condition than in the non-rapport building condition. Based on this study's results, we discussed the importance of rapport building in the pre-interview phase of a polygraph test and the need to operationalize verbal and non-verbal rapport building techniques.

• Korean Journal of Cognitive Science
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• v.35 no.1
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• pp.49-95
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• 2024

Polygraph examination, statement validity analysis and P300-based concealed information test are major three examination tools, which are use to determine a person's truthfulness and credibility in criminal procedure. Although polygraph examination is most common in criminal procedure, but it has little admissibility of evidence due to the weakness of scientific basis. In 1990s to support the weakness of scientific basis about polygraph, Farwell and Donchin proposed the P300-based concealed information test technique. The P300-based concealed information test has two strong points. First, the P300-based concealed information test is easy to conduct with polygraph. Second, the P300-based concealed information test has plentiful scientific basis. Nevertheless, the utilization of P300-based concealed information test is infrequent, because of the quantity of probe stimulus. The probe stimulus contains closed information that is relevant to the crime or other investigated situation. In tradition P300-based concealed information test protocol, three or more probe stimuli are necessarily needed. But it is hard to acquire three or more probe stimuli, because most of the crime relevant information is opened in investigative situation. In addition, P300-based concealed information test uses oddball paradigm, and oddball paradigm makes imbalance between the number of probe and irrelevant stimulus. Thus, there is a possibility that the unbalanced number of probe and irrelevant stimulus caused systematic underestimation of P300 amplitude of irrelevant stimuli. To overcome the these two limitation of P300-based concealed information test, one-probe P300-based concealed information test protocol is explored with various machine learning algorithms. According to this study, parameters of the modified one-probe protocol are as follows. In the condition of female and male face stimuli, the duration of stimuli are encouraged 400ms, the repetition of stimuli are encouraged 60 times, the analysis method of P300 amplitude is encouraged peak to peak method, the cut-off of guilty condition is encouraged 90% and the cut-off of innocent condition is encouraged 30%. In the condition of two-syllable word stimulus, the duration of stimulus is encouraged 300ms, the repetition of stimulus is encouraged 60 times, the analysis method of P300 amplitude is encouraged peak to peak method, the cut-off of guilty condition is encouraged 90% and the cut-off of innocent condition is encouraged 30%. It was also conformed that the logistic regression (LR), linear discriminant analysis (LDA), K Neighbors (KNN) algorithms were probable methods for analysis of P300 amplitude. The one-probe P300-based concealed information test with machine learning protocol is helpful to increase utilization of P300-based concealed information test, and supports to determine a person's truthfulness and credibility with the polygraph examination in criminal procedure.

• The Journal of the Korea Contents Association
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• v.11 no.5
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• pp.384-392
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• 2011

Recruitment and selection are separate but mutually reinforcing processes. The goal of recruitment is to attract the largest number of applicants possible to apply to the agency, and selection is the process of weeding out unqualified candidates and identifying qualified candidates. In this context, the recruitment and selection system of police officials is an important issue because it affects their future performance as police officers on the job, especially their policing skills, perception of society, occupational ethics. This study suggested the characteristics of U. S. recruitment and selection system of police officials. In the U. S, each police agency sets up its own recruitment and selection standards and procedures. However, recruitment and selection process follows a certain sequence : receiving application, psychological examination, background check, polygraph test, drug screening, interview, physical agility, and medical test. Special characteristic of American police system regarding recruitment and selection is that many law enforcement agencies use a polygraph test to ensure the integrity of the candidates. Another interesting screening process is a drug test because many Americans abuse illegal drugs. A candidate officer must submit urine or a hair sample for screening test. Police human resources specialists should continually identify the most innovative tests and approaches recruit and select police officers. Recruitment and selection strategies should increasingly attract and retain those officers who have the attributes to work in a community-oriented policing environment.

• Korean Journal of Animal Reproduction
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• v.18 no.2
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• pp.101-104
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• 1994

The purpose of the present study was to examine the in vivo activity of oxytocin antagonist I (AI)in the nonpregnant estrous rat. Cannulas were placed in the jugular vein for infusing compounds and a water-filled balloon-tipped cannula placed in one uterine horn for assessing uterine activity. Uterine contractions were monitored with a Grass Polygraph and contractile activity determined as the integrated area for 10 minutes. Five minutes after infusing 5 ${\mu}\textrm{g}$ of AI, 100mU of oxytocin was given as an in bolus injection and repeated every hour for 5 hours. At five minutes, 1 and 2 hours after injection AI the uterine contractile response to 100 mU of oxytocin was significantly inhibited compared to controls(p<0.05). At 3, 4 and 5 hours no differences in response were detected compared to controls(p>0.05). These results in conjunction with other reports from our laboratory suggest that AI has the potential of being a potent and specific tocolytic for prevention of preterm labor in humans.

• Anxiety and mood
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• v.4 no.2
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• pp.99-103
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• 2008

Objectives : The authors sought to examine the differences in the number of P300 detected by subjects in experimental and control groups when exposed to relevant stimuli. In addition, the authors tried to determinethe subjects' reaction time when asked to respond to relevant stimuli. Methods : The subjects were 20 informed female volunteers aged 22-38 years (median age : 24). Relevant stimuli (concealed information) were created by unknowingly exposing the two groups to obscene pictures and semantic questions. The number of P300 detected and the length of reaction time were compared between the two groups. Results : Contrary to theauthors' expectations, there were no significant differences in the number of P300 detected or in the length of reaction time between the two groups. Conclusions : These results indicate that, unlike a polygraph test, concealed information tests adopting P300 and reaction time as major physiological responses ofsubjects exposed to meaningful personal information might not serve as a valid practical tool in the field of criminal psychology. However, further studies involving a greater number of subjects are needed before a final conclusion regarding the validity of this new type of concealed information test can be drawn.