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In this study, we propose a deceptive jamming method for satellite-borne synthetic aperture radar (SAR) using SAR signal parameters estimated based on recursive least squares estimation (RLSE). Unlike traditional modulation retransmission-based deceptive jamming methods, the proposed method estimates the parameters required for deceptive jamming in real-time and generates deceptive signals using these estimated parameters. Deceptive signals were emitted before the SAR signals were intercepted. This approach enables deceptive jamming even without exact prior knowledge of the SAR signal parameters and allows the formation of false targets ahead of the jammer along the range direction. To assess the effectiveness of the proposed method, we conducted simulations to focus on false-point targets and analyzed the results using SAR image quality measurements. [ABSTRACT FROM AUTHOR]

This article discusses studies and real-world experiences related to the clinical application of artificial intelligence-based computer-aided detection (AI-CAD) software (LuCAS-plus, Monitor Corporation) in detecting pulmonary nodules. During clinical trials for lung cancer screening, AI-CAD exhibited performance comparable to that of medical professionals in terms of sensitivity and specificity. Studies revealed that applying AI-CAD for diagnosing pulmonary metastases led to high detection rates. The use of a nodule matching algorithm in diagnosing pulmonary metastases significantly reduced false non-metastasis results. In clinical settings, implementing AI-CAD enhanced the efficiency of pulmonary nodule detection, saving time and effort during CT reading. Overall, AI-CAD is expected to offer substantial support for lung cancer screening and the interpretation of chest CT scans for malignant tumor surveillance. [ABSTRACT FROM AUTHOR]

As numerous synthetic aperture radar (SAR) satellites have been launched to secure surveillance and reconnaissance capabilities, considerable research has focused on SAR jamming methods. In particular, methods that utilize the received SAR signals for deceptive jamming have drawn increasing attention. However, because these methods perform deceptive jamming after the SAR signal is received, they cannot create a false target ahead of the jammer along the range axis. Accordingly, as part of the research on deceptive jamming methods to overcome this limitation, this study aims to estimate the transmission time of the next SAR signal and the center frequency in real time from the received SAR signal. The proposed method precisely estimates these parameters using pulse compression and recursive least squares estimation, and the estimation results are confirmed through simulations. [ABSTRACT FROM AUTHOR]

The use of radio frequency (RF) communications and radar signals with multiarray antennas is increasing. The array antennas used in these applications should be sophisticatedly matched in terms of the phase and amplitude for beam steering. In particular, phase and amplitude matching are the core techniques of cross-eye jamming that is known to cause angle deception in radars and missiles with monopulse sensors, resulting in wavefront distortion. In this study, to improve the beam steering performance of typical transceivers with phased array antennas and generate large angle errors in systems with monopulse sensors, a novel architecture to precisely match the phases and amplitudes of multichannel transceiver array antennas in the dual-frequency band is proposed, and the performance is verified using the fabricated device. [ABSTRACT FROM AUTHOR]

In this study, we propose a methodology for training a deep learning model using historical time series data to predict current values. Using 11,942 past meteorological observations collected over a specific period from the Osan weather station in Gyeonggi-do, we predicted the atmospheric radio refractivity at the current time. As a result of predicting the atmospheric radio refractivity at 00Z on August 4, 2023, and August 5, 2023, at the Osan weather station in Gyeonggi-do, the average MAPE(mean absolute percentage error) and ARIMA(autoregressive integrated moving average) of the proposed model were 2.75 % and 7.61 %, respectively. [ABSTRACT FROM AUTHOR]

In this study, we propose a model for predicting atmospheric refractivity using meteorological data and deep learning. The purpose of this study is to compare the prediction accuracy of traditional interpolation methods and the proposed model, verify whether the deep learning model trained on meteorological data can provide values closer to the true values, and thus demonstrate the potential for utilizing deep learning in predicting atmospheric refractivity. [ABSTRACT FROM AUTHOR]

Pancreatic stones are a common finding of chronic pancreatitis and may cause recurrent abdominal pain and pancreatitis. Pancreatic stones are often accompanied by stenosis of the pancreatic duct and are often impacted within the pancreatic duct, so it is not easy to remove the pancreatic stones using a basket. Until now, extracorporeal shock wave lithotripsy has been used, but it requires repeated procedures and the success rate is not very high. The recently developed SpyGlass™ DS II (Boston Scientific, Marlborough, MA, USA) has a 3.5 mm diameter that allows insertion into the dilated pancreatic duct, it is possible to remove the pancreatic stones using electrohydraulic lithotripsy (EHL) or laser lithotripsy while directly viewing the pancreatic stones. In this paper, we would like to introduce a method to remove multiple pancreatic stones larger than 10 mm using SpyGlass™ DS II with EHL. [ABSTRACT FROM AUTHOR]

In this study, we investigate the latest trends in satellites, ground stations, and antennas that transmit high-capacity image data at a high-resolution. Various data transmission/reception satellites and ground station antennas are investigated, and radio-wave transmission scenarios applicable to the Korean Multi-purpose Satellite 5 (KOMPSAT-5) are determined. The datalink budget is then calculated as the signals are transmitted by the KOMPSAT-5 and received by a Singapore ground station using a parabolic-type antenna. When the data transmission distance is increased from 550 km to a maximum of 2,200 km, the minimum and maximum received powers using a helix transmit antenna are −68.1 dBm and −55.9 dBm, respectively. By contrast, when the satellite transmit antenna is a patch array, the minimum and maximum received powers are −84.1 dBm and −71.9 dBm, respectively. [ABSTRACT FROM AUTHOR]

Purpose In the adult emergency department of a university hospital, we investigated the frequency of major discrepancies between the preliminary reports by radiology residents and the final reports by certified radiologists. Materials and Methods Based on CT and MRI scans obtained between December 2016 and November 2019, we selected cases with diagnoses or treatment plans that could be changed due to discrepancies between preliminary and final reports and classified them by the type of discrepancy. We also examined the distributions of the major discrepancies and stratified them by residents’ working time zone, experience, and subspecialty. Results Based on the 72137 preliminary reports evaluated, 1348 tests (1.9%) showed major discrepancies. Most of the major discrepancies were false negatives (72.0%), followed by misdiagnosis (26.3%) and false positives (1.7%). Acute findings (87.2%) were more common than nonacute findings (12.8%). The major discrepancy rate increased toward the second half of the 24-hour shift, with the highest rate of 2.9% occurring between 2 am and 4 am. The major discrepancy rate did not vary with experience, and it varied from 0.6% to 4.5% for each subspecialty. Conclusion The major discrepancy rate was less than 2%, and it increased with longer working hours during a 24-hour shift. [ABSTRACT FROM AUTHOR]

This paper proposes an alternative method for measuring the frequency of a short-time signal in a wideband frequency range. A frequency measuring architecture comprising multiple sub-Nyquist sampling channels and a frequency estimator is proposed. The simulation results show that the proposed method has better frequency accuracy, though it uses lower sampling rates than typical DFDs for wideband input frequency range. [ABSTRACT FROM AUTHOR]

This study evaluated soccer-specific fitness early and late season to check the conditioning status of K3 league soccer players. Evaluation factors included body composition, agility, quickness, endurance and isokinetic limb muscle strength. As a result, the factors that showed improvement in the late season were skeletal muscle mass, agility and quickness, and body composition, endurance and isokinetic limb muscle strength were not different from each other. The factors that showed improvement in the second half of the season are thought to be due to the learning effect of repetitive training, competition participation during the season. Lastly, endurance and lower extremity strength did not show improvement in the second half of the season due to the fact that no specific training was performed during the season. Taken together, it is necessary to periodically check the fitness status of athletes to develop and apply a fitness training program suitable for competition, transition and preparation period. [ABSTRACT FROM AUTHOR]

Purpose: The Act on Hospice and Palliative Care and Decisions on Life-sustaining Treatment for Patients at the End of Life was enacted in 2016 and has taken effect since 2018 February. The content of this act was based on Physician Orders for Life-Sustaining Treatment (POLST) in the United States and we modified it for terminal cancer patients registering hospice. The object of this study is to investigate preference and implementation rate for modified Korean POLST (MMK-POLST) items in hospice ward. Methods: From February 1, 2017 to April 30, 2019, medical records regarding MMK-POLST were retrospectively analyzed for all patients hospitalized in the hospice ward of Gyeongsang National University Hospital. Results: Of the eligible 387 total cohorts, 295 patients filled out MK-POLST. MK-POLST has been completed in 133 cases (44.1%) by the patient themselves, 84 cases (28.5%) by the spouse, and 75 cases (25.4%) by their children, respectively. While only 13 (4.4%) out of 295 MKPOLST completed patients refused the parenteral nutrition and 5 patients (1.7%) for palliative sedation, the absolute majority of 288 (97.6%) patients did not want cardiopulmonary resuscitation (CPR) and ventilators and 226 people (76.9%) for pressor medications. Kappa values for the matched strength of MK-POLST implementation were poor for all items except CPR, ventilators and palliative sedation. Conclusion: Hospice patients refused to conduct cardiopulmonary resuscitation, ventilators and pressor agents. In contrast, antibiotics, parenteral nutrition and palliative sedation were favored in the majority of patients. [ABSTRACT FROM AUTHOR]

This study analyzes the influential factors and patterns associated with death from aircraft accidents and incidents using data mining techniques. To this end, we used two datasets for aircraft accidents and incidents, one from the National Transportation Safety Board (NTSB) and the other from the Federal Aviation Administration (FAA). We developed our prediction models using the decision tree classifier to predict death from aircraft accidents or aircraft incidents and thereby derive the main cause factors and patterns that can cause death based on these prediction models. In the NTSB data, deaths occurred frequently when the aircraft was destroyed or people were performing dangerous missions or maneuver. In the FAA data, deaths were mainly caused by pilots who were less skilled or less qualified when their aircraft were partially destroyed. Several death-related patterns were also found for parachute jumping and aircraft ascending and descending phases. Using the derived patterns, we proposed helpful strategies to prevent death from the aircraft accidents or incidents. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the effects of muscle asymmetry of knee joint among elite cyclists on anaerobic pedaling power related capacity. In another word, based on isokinetic strength of Non-Dominant, ND and Dominant, D, side, high, moderate and low ratio of ND to D were classified as High Symmetry Group, Moderate Symmetry Group and Asymmetry Group, respectively. Analysis of muscle asymmetry of extensor’s ND and D side might not lead to any difference between the three groups. Based on muscle strength analysis of the flexor’s ND and D, there was statistical difference between the groups in ND flexor and in the muscle balance index of the flexor muscle. This result also leads to significant difference in pedaling power functionality, but this effects might not lead to any negative pedaling power. Therefore, among even cyclists who may show almost the same recruitment pattern of ND and D side during pedaling stroke muscle asymmetry could exist but this phenomena might not negatively contribute to the pedaling capacity. [ABSTRACT FROM AUTHOR]

Purpose: To compare the results of two different instruments made of stainless steel and titanium alloy for correction of single thoracic adolescent idiopathic scoliosis (AIS) using pedicle screw instrumentation. Materials and Methods: A total of 141 patients with single thoracic AIS treated with pedicle screw instrumentation and selective thoracic fusion were retrospectively reviewed after a follow-up of 2 years. The patients had a main thoracic curve of 40° to 75° and were divided into two groups based on instrument materials; S group (stainless steel, n=90) and T group (titanium alloy, n=51). The diameter of the stainless steel rod used was 7.0 mm while that of the titanium alloy rod was 6.35 mm or 6.0 mm. Standing long-cassette radiographic measurements including various coronal and sagittal parameters for the preoperative, early postoperative and 2-year postoperative followup were analyzed. There were no significant differences in the preoperative curve characteristics between the two groups. Results: In the S group, the preoperative main thoracic curve of 51.3°±8.4° was improved to 19.0°±7.6° (63.1% correction) and the lumbar curve of 32.3°±8.4° spontaneously decreased to 12.7°±8.2° (62.9% correction) at 2 years postoperatively. In the T group, the preoperative main thoracic curve of 49.5°±8.4° and the lumbar curve of 30.3°±8.9° was improved to 18.8°±7.4° (62.2% correction) and 11.3°±5.4° (63.3% correction), respectively. The corrections of coronal curves were not statistically different between the two groups (p>0.05). The thoracic kyphosis was changed from 16.8°±8.5° to 24.3°±6.1° in the S group and from 19.6°±11.2° to 26.6°±8.5° in the T group. There were no significant differences in the changes of sagittal curves, coronal and sagittal balances at the 2-year follow-up and the number of fused segments and used screws between the two groups (p>0.05). Conclusion: When conducting surgery for single thoracic AIS using pedicles screw instrumentation, two different instruments made of stainless steel and titanium alloy showed similar corrections for coronal and sagittal curves. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study is to identify the influence of chronotype and self-efficacy on drinking problem in undergraduate students. Methods: A cross-sectional survey design was adopted for the 177 undergraduate students in D, G, and K city in 2017. The data was analyzed for descriptive statistics, t-test, ANOVA, Pearson’s correlation coefficients and multiple regression analysis using the SPSS 18.0 program. Results: Chronotype (β=-.31, p<.001), self-efficacy (β=27, p<.001) and religion (β=-.19, p=.005) were identified as the factors influencing drinking problem in the subjects. The model explained 19% of variance in drinking problem (F=11.36, p<.001). Conclusion: It is necessary to develop and apply a program that would consider chronotype and self-efficacy factors to reduce the drinking problem in undergraduate students. [ABSTRACT FROM AUTHOR]

Opioid aberrant behavior is an emerging problem as strong opioid is increasingly used to alleviate cancer pain in patients with cancer. Although the treatment of opioid addiction and physical dependence for non-cancer pain is well known, few studies have been conducted with cancer patients, particularly in the Korean population. Presented here are ten cases of cancer patients who were physically dependent on strong opioid and successfully treated with a partial mu-opioid receptor agonist, buprenorphine. This is the first report showing the efficacy of transdermal buprenorphine as a treatment for physical dependence on opioid medication in cancer patients. [ABSTRACT FROM AUTHOR]

This report is a case of 38-year old female patient who had a chief complaint about having pronounciation disorder after going under mass excision due to mucoepidermoid carcinoma. She was referred to department of prosthodontics, Yonsei university. Palatal lift prosthesis was fabricated which was then relined with tissue conditioner. Evaluations on phonetics and swallowing were done and improvements were shown. Tissue conditioner was replaced with heat polymerizing resin and the patient was satisfied with the results of treatment [ABSTRACT FROM AUTHOR]

Recently, deep learning algorithms have good performance in various fields, but they are not actively applied to sonar systems. In this study, we carried out experiments to classify active sonar returns into a metal object such as a mine and a rock using a convolutional neural network which is one of the deep learning algorithms. Data augmentation is applied on this paper to avoid overfitting and increase performance. And we analyzed performance variation depending on hyperparameter value and change of the number of training data through data augmentation. The experiments are performed with two training data; an aspect-angle independent and an aspect-angle dependent. As a result, the performances are 88.9% and 94.9% in aspect-angle independent and dependent, respectively. These are up to 4.5% point higher than the performance obtained by applying artificial neural network and support vector machine algorithm in the previous study. [ABSTRACT FROM AUTHOR]

Purpose: Oral naloxone is combined with oxycodone to alleviate or prevent opioid-induced constipation in cancer pain patients. However, there is still concern that oral naloxone may precipitate opioid withdrawal symptoms in patients on opioids. We retrospectively investigated clinical characteristics of cancer patients who experienced opioid withdrawal symptoms. Methods: We reviewed medical records of all patients who were prescribed with oral oxycodone/naloxone at a tertiary cancer center from January 1, 2012 through December 31, 2016. Eligible patients were screened based on demographics, opioid and naloxone dosages, clinical manifestation and pain intensity. Results: Among a total of 1,641 patients, 10 patients were selected. Seven patients were male, and the average age was 68.1 years. The median dose of naloxone that induced withdrawal symptoms was 20 mg. Most common withdrawal symptom was shivering (seven patients) followed by cold sweating (five), and muscle twitching (five). Other symptoms included restlessness, fever, dizziness, and yawning. Pain was exacerbated from the median intensity of numeric rating scale (NRS) 3 to NRS 6. Conclusion: Opioid withdrawal symptoms may occur when switching to oral oxycodone/naloxone for cancer patients who have been treated with other strong opioids. A prospective, multicenter study on this issue should be conducted in future. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to analyze the clinical results of medial horizontal suture fixation of Akin osteotomy in hallux valgus and present its advantages. Materials and Methods: This study was based on 48 cases of 35 patients with Akin osteotomy, who underwent surgery of hallux valgus between December 2014 and July 2015, and with at least 12 months of follow-up. The mean age of patients was 46.9 years (range, 16-71 years). The mean follow-up duration was 15.9 months (range, 12-18 months). Clinical evaluations included pain visual analogue scale (VAS) score, American Orthopaedic Foot and Ankle Society (AOFAS hallux metatarsophalangeal interphalangeal scale) score, and satisfaction score. Weightbearing anteroposterior radiographs were taken to measure the distal articular set angle (DASA) of the hallux. Radiographic bone union at 6 months follow-up was regarded as a success, while a loss of reduction and nonunion was regarded as a failure. Results: The mean pre- and postoperative pain VAS scores were 4.27 and 1.67, respectively (p<0.05). The mean AOFAS score improved from 59.7 to 80.5 (p<0.05). The DASA was improved from 8.15 to -2.57 (p<0.05). There was no case of skin irritation, cortical breakage, inflammation from the knot, and infection. All patients showed union without fixation failure. Conclusion: The clinical and radiological evaluations in this study demonstrate reliable results without complication. The medial horizontal suture fixation of the Akin osteotomy was effective, and the advantage of this procedure was unnecessity of the material removal, preservation of the joint, and no skin irritation. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the clinical outcomes of distal hook augmentation using a pedicle screw in thoracolumbar fusion in elderly patients. Materials and Methods: This retrospective multicenter study recruited 20 patients aged 65 years or older, who underwent anterior support and long level posterior fusion in the thoracolumbar junction with a follow-up of one year. To assess the effect of distal hook augmentation, the patients were divided into two groups; the pedicle screw with hook group (PH group, n=10) and the pedicle screw alone group (PA group, n=10). Results: The average age was 72.4 years (65-83 years). The average fusion segment was 4.6 segments (3-6 segments). There were no significant differences in age, sex, causative diseases, bone mineral density of lumbar and proximal femur, number of patients with osteoporosis, and number of fused segments between the two groups (p≥0.05). At 1 year follow-up after surgery, parameters related with distal screw pullout were significantly worse in the PA group. No patients in the PH group had distal screw pullout. However, six patients (60%, 6/10) in the PA group had distal screw pullout. There were no significant differences in the progression of distal junctional kyphosis between the two groups. Conclusion: Distal hook augmentation is an effective procedure in protecting distal pedicle screws against the pullout when long level thoracolumbar fusion was performed in elderly patients aged 65 years or older. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the risk factors for subsequent vertebral fracture following acute osteoporotic vertebral compression fracture. Materials and Methods: This was a multicenter retrospective study. We recruited 135 patients treated for acute osteoporotic compression fracture with available spine image taken at the 1-year follow-up mark in 3 different hospitals. The patients were divided into 2 groups in accordance with the occurrence of subsequent vertebral fracture. Variables including age, sex, bone mineral density, medical comorbidity, acute fracture level, presence of prior vertebral fracture, osteoporosis medication, and treatment method were analyzed and compared between the 2 groups. Results: The new subsequent vertebral fractures were detected in 25 patients (18.5%). There were no significant differences between the 2 groups with respect to age, sex, medical comorbidity, presence of prior vertebral fracture, and acute fracture level, as shown by univariate analysis. However, in the group with subsequent vertebral fracture, more patients were treated by vertebroplasty or kyphoplasty and had a femur neck T-score of ≤-2.5, as well as poor compliance of osteoporosis medication with significant difference (p＜0.05). According to the multivariate analysis, subsequent vertebral fractures were significantly influenced by vertebroplasty or kyphoplasty (p=0.003, odds ratio=4.71) and femur neck T-score of ≤-2.5 (p=0.013, odds ratio=3.47). Conclusion: Subsequent vertebral fractures were found in 19% at the 1-year mark after the treatment of acute osteoporotic compression fracture. The two risk factors for subsequent vertebral fractures were vertebroplasty or kyphoplasty and femur neck T-score of ≤-2.5. [ABSTRACT FROM AUTHOR]

With the development of nanotechnology, the amount of nanomaterials increases and the problems of environment and the toxic property associated with it have become a social problem. But regulations and laws of nanomaterials have not yet been established. The purpose of this study is to utilize as the database of safety guidelines for research activities' workers associated with nanomaterials to conduct a behavior evaluation of aluminium oxide, which is most widely used in thirteen kinds of WPMN manufactured nanomaterials in the country. The experiment proceeds in the chamber reduced to 1/6 size of the actual laboratory, the test method was performed in NIOSH 0500. As the results of the study, the mass concentration was in inverse proportion to the particle size of the nanomaterials. And the mass concentration during the operation of ventilation equipment was reduced to about 1/8 times. In the future, it can be utilized as the database of safety guidelines for research activities' workers associated with nanomaterials. However, in order to increase the reliability of the study, the experiment of the mass concentration by particle size and Condensation Particle Counters will be needed additionally. [ABSTRACT FROM AUTHOR]

Background and Objectives: Sinus surgery has been reported to improve pulmonary function and decrease the use of asthma medications in patients with chronic rhinosinusitis and asthma. Most studies, however, have used a small number of patients and were conducted over a short period. To demonstrate a causal relationship between sinus surgery and asthma, a sufficient amount of patient data observed over a long period is required. To address the limitations of the existing approaches, we conducted a preliminary methodological study for large-scale data analysis using data from the National Health Insurance Service (NHIS) to suggest a basis for the effect of sinus surgery on asthma. Materials and Methods: The data from NHIS consisted of unidentified medical histories of a sample cohort representing the whole nation over a period of nine years. We selected the following types of study samples: 1) patients with surgical codes for sinus surgery; 2) patients with disease codes for sinusitis; 3) patients with disease codes for asthma; and 4) patients with medication codes for asthma treatment. Results：In this study, we applied a methodology for selection of subjects from big data to investigate the effect of sinus surgery on improving asthma in the future. We could include 152 subjects after the four-stage selection method from 1,025,340 patients. Conclusion: We could establish a method to select patients with history of sinus surgery and asthma treatment from a big data. This methodology using big data may contribute to identify relationship between sinus surgery and asthma treatment in the future. [ABSTRACT FROM AUTHOR]

This paper proposes a high speed frequency synthesizer with dual phase-locked loop(PLL) structure to improve phase noise level and shape in a wideband receiver. To reduce phase noise and fractional spur, a output frequency of 1st PLL used as reference frequency of 2nd PLL is changed. The frequency synthesizer has been designed with 1 Hz frequency resolution using digital NCO in 6.5～8.5 GHz wide spectrum. The measured results of the fabricated frequency synthesizer show that the output power is about —3 dBm, the maximum lock-in time and phase noise are within 60 us and —95 dBc/Hz at 10 kHz offset, respectively. [ABSTRACT FROM AUTHOR]

One fourth of cases of non-Hodgkin lymphoma were reported as extranodal type and skeletal muscle involvement rarely seen as a primary event and local dissemination. The psoas involved lesion with spine mimicking pain is caused mainly by infection rather than non-infected conditions such as tumor. We report on a rare case of non-Hodgkin lymphoma occurring in psoas muscle, which required differentiation from a psoas abscess. [ABSTRACT FROM AUTHOR]

Purpose In the adult emergency department of a university hospital, we investigated the frequency of major discrepancies between the preliminary reports by radiology residents and the final reports by certified radiologists. Materials and Methods Based on CT and MRI scans obtained between December 2016 and November 2019, we selected cases with diagnoses or treatment plans that could be changed due to discrepancies between preliminary and final reports and classified them by the type of discrepancy. We also examined the distributions of the major discrepancies and stratified them by residents’ working time zone, experience, and subspecialty. Results Based on the 72137 preliminary reports evaluated, 1348 tests (1.9%) showed major discrepancies. Most of the major discrepancies were false negatives (72.0%), followed by misdiagnosis (26.3%) and false positives (1.7%). Acute findings (87.2%) were more common than nonacute findings (12.8%). The major discrepancy rate increased toward the second half of the 24-hour shift, with the highest rate of 2.9% occurring between 2 am and 4 am. The major discrepancy rate did not vary with experience, and it varied from 0.6% to 4.5% for each subspecialty. Conclusion The major discrepancy rate was less than 2%, and it increased with longer working hours during a 24-hour shift. [ABSTRACT FROM AUTHOR]