• Title/Summary/Keyword: False-negative results

Search Result 303, Processing Time 0.024 seconds

Metal pad Discolored Image Classification Algorithm using Geometric Texture Information (기하학적 텍스쳐 정보를 이용한 금속 패드 변색영상 분류 알고리즘)

  • Cui, Xue Nan;Kim, Hak-Il
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.16 no.5
    • /
    • pp.469-475
    • /
    • 2010
  • This paper presents a method of classifying discolored defects of metal pads using geometric texture for AFVI (Automated Final Vision Inspection) systems. In PCB manufacturing process, the metal pads on PCB can be oxidized and discolored partly due to various environmental factors. Nowadays the discolored defects are manually detected and rejected from the process. This paper proposes an efficient geometric texture feature, SUTF (Symmetry and Uniformity Texture Feature) based on the symmetric and uniform textural characteristics of the surface of circular metal pads for automating AFVI systems. In practical experiments with real samples acquired from a production line, 30 discolored images and 1232 roughness images are tested. The experimental results demonstrate that the proposed method using SUTFs provides better performance compared to Gabor feature with 0% FNR (False Negative Rate) and 1.46% FPR (False Positive Rate). The performance of the proposed method shows its applicability in the real manufacturing systems.

Association between False Positive, False Negative, High-Background Cases and Humidity in One Lambda LABTypeTM HLA-DR Typing (One Lambda LABTypeTM을 이용한 HLA- DR Typing시 나타나는 위양성과 위음성, High-Background 사례와 검사실 습도의 관계분석)

  • Hyang Son AN;Minsung SOHN
    • Korean Journal of Clinical Laboratory Science
    • /
    • v.55 no.3
    • /
    • pp.132-142
    • /
    • 2023
  • Human leukocyte antigen (HLA) typing was performed in the diagnostic immunology laboratory of the Seoul National University Hospital. Among 611 HLA-DR tests, specific bead reactions suspected of being false positive and false negative in Lot 20 reagents were found. Therefore, we aimed to identify the factors causing cut-off corrections by examining cases where cut-off corrections were not made for 533 test results and cases where cut-off corrections were made for 78 cases after the cut-off corrections of specific beads. Frequency analysis was conducted to verify the demographic characteristics, and descriptive statistics were used to assess the humidity in the laboratory as a variable. Cross-tabulation was done to examine the association between cut-off corrections and demographic characteristics. Independent samples t-tests were conducted to verify the difference in humidity based on cut-off corrections. Finally, logistic regression analysis was conducted to examine the relationship between humidity levels and the rate of cut-off corrections, and results showed as the humidity level in the laboratory highs, the number of cut-off corrections decreased by a factor of 0.986. This suggests cut-off corrections rate increases when the humidity lowers. Therefore, it indicates that humidity in the laboratory is also a factor that affects HLA typing results.

The Significance of Serum Thyroid Peroxidase as a New Tumor Marker in Papillary Thyroid Carcinoma after Thyroidectomy (유두상 갑상선암의 수술후 재발예측인자로서 혈청 Thyroid Peroxidase의 의의)

  • Chang Hang-Seok;Na Jae-Wung;Chung Woong-Youn;Park Cheong-Soo
    • Korean Journal of Head & Neck Oncology
    • /
    • v.15 no.1
    • /
    • pp.46-51
    • /
    • 1999
  • Background: Total thyroidectomy and postoperative radiodiodine ablation therapy in differentiated thyroid carcinomas enhance the reliability of serum thyroglobulin(Tg) levels and radioiodine scan in detecting recurrence or distant metastasis. There have been, however, some limitations in using these methods under certain conditions. Recently, several reports have indicated that thyroid peroxidase(TPO) could be used as an alternative tumor marker. We aimed to estimate the significance of serum TPO levels in differentiated thyroid carcinoma. Materials and Methods: Forty-eight patients who had undergone total thyroidectomy due to papillary thyroid carcinomas and who had been followed-up for at least 3 years were classified into two groups: 27 patients without any evidence of recurrence in group 1; and 20 patients with recurrence or distant metastasis in group 2. All patients were examined by radioiodine scans. Serum Tg, TSH, antithyroglobulin antibody, and TPO were measured and the relationships were statistically analyzed. The sensitivity and specificity of $^{131}I$ scan, serum Tg, and serum TPO were evaluated. Results: Serum Tg levels were $3.81{\pm}5.16ng/mL$ in group 1 and $147.02{\pm}193.75ng/mL$ in group 2. Only 2 patients in group 1 showed Tg levels exceeding 10ng/mL. In contrast, 4 patients in group 2 were under 10ng/mL. Serum antithyroglobulin antibody and TSH levels showed no statistical difference between the two groups. In group 1, 16 patients showed negative serum TPO results, and 4 patients in group 2 showed negative results. There was no correlation among serum Tg levels, antithyroglobulin antibody titers, and serum TPO levels in each group. In group 2, 4 patients with negative serum Tg levels showed positive TPO results and positive whole body scans. Two cases with false negative $^{131}I$ scans showed positive serum TPO and Tg results. In 4 cases showing false negative serum TPO levels, serum Tg levels and $^{131}I$ scans were positive. Conclusion: Serum Tg levels, radioiodine scans, and serum TPO levels can be clinically used as complementary methods in the diagnosis of recurrent or metastatic thyroid carcinomas. Serum TPO levels may be helpful when other methods fail to detect recurrences or distant metastasis in highly suspected patients.

  • PDF

Thallium-201 Scan in Bone and Softtissue Sarcoma - Comparison with Tc-99m-MIBI and Tc-99m-MDP Scan - (악성 골 및 연부조직 종양에서 Tl-201 SCAN의 진단적 효능 - Tc-99m-MIBI 및 Tc-99m-MDP scan과의 비교 -)

  • Shin, Duk-Seop;Cho, Ihn-Ho;Ahn, Jong-Chul;Ahn, Myun-Hwan;Lee, Sang-Ho
    • The Journal of the Korean bone and joint tumor society
    • /
    • v.2 no.1
    • /
    • pp.1-7
    • /
    • 1996
  • PURPOSE : The purpose of this study is to know the ability of detecting malignant tumor tissue by Tl-201 scan, and to compare with that of Tc-99m-MIBI and Tc-99m-MDP scan. MATERIAL AND METHODS : Between February 1994 and December 1995,38 unselected patients with various bone pathologies were studied prospectively. Eighteen had malignant bone and soft tissue pathologies, while twenty had benign. All patients were studied with Tl-201, Tc-99mMIBI and Tc-99m-MDP scan prior to surgical biopsy. PICKER Prism 2000 gamma camera with high resolution parallel hole collimator was used for scanning. To avoid the interaction of isotope, the early(30min.) and delayed phase(3hrs.) of Tl-20l scan was performed first and Tc-99m-MIBI scan was performed after 30 minutes, and then Tc-99m-MDP scan 48 hours later. The scan images were visually evaluated by a blinded nuclear medicine physician. We could find true positive, true negative, false positive and false negative by the comparison of results with those of biopsy. We calculated positive and negative predictive value(%), sensitivity(%), specificity(%) and diagnostic accuracy(%) of each scan. RESULT : The results of each scan were 85.7, 100, 100, 85, 92.1% in Tl-201, 81, 94.1, 94.4, 80, 86.8% in Tc-99m-MIBI and 50, 66.7, 88.9, 20, 52.6% in Tc-99m-MDP scan. As a conclusion, Tl-201 scan was the most specific and accurate method for detecting malignant tumor tissue. Tc-99m-MIBI scan was also good for malignant tumor searching. CONCLUSION : With our results, we can use Tl-201 scan to differentiate benign from malignant tumor, and to evaluate the response of preoperative chemotherapy or radiotherapy, and to determine the residual tumor or local recurrence. For the better result, we need to have a more detail information about false positive cases and a more objective and quantitative reading technique.

  • PDF

Validity of Needle Aspiration Cytology and Frozen Section in Thyroid Tumor (갑상선 결절에서 세침흡인검사와 동결조직검사의 의의)

  • Kim Jae-Won;Lee Jang-Won;Bae Sung-Ho;Ko Kook-Jin;Yoon Suk-Young;Kim Young-Mo
    • Korean Journal of Head & Neck Oncology
    • /
    • v.20 no.2
    • /
    • pp.143-146
    • /
    • 2004
  • Background and Object: The role of fine needle aspiration cytology (FNAC) and frozen section (FS) in management of thyroid neoplasms continues to generate considerable controversy. We reviewed our current experience to determine the clinical utility of FNAC and FS in our surgical management and investigated reliability of FNAC and FS in planning the extent of thyroid resection. Material and Method: 212 patients who had operations for thyroid disease from May 1996 to November 2003 were included our retrospective study. FNAC was undertaken in 175 patients and FS was done in 148 patients. Result: The sensitivity and specificity of FNAC were 72.1% and 100%, respectively, and those of FS were 67.2% and 100%. The results of FNAC were benign (n=72) , malignancy (n=31), indeterminate (n=9), and nondiagnostic (n=63). The results of FS were benign (n=95), and malignancy (n=53). The 9 indeterminate cases on FNAC were benign (n=6) and malignancy (n=3) on final pathology, and benign (n=7) and malignancy (n=2) on FS. The false negative of FNAC were micro papillary carcinoma (n=6) and follicular carcinoma (n=6). The false negative of FS were micropapillary carcinoma (n=10) and follicular carcinoma (n=2). Conclusion: When results of FNAC are interpreted as indeterminate, FS is a valuable tool. FS is helpful in determining the extent of thyroidectomy when results of FNAC were follicular neoplasm. However we always concerned about micropapillary carcinoma and follicular carcinoma although FNAC and FS were benign.

Detection of Methicillin-resistant Staphylococcs aureus from the Anterior Nares of Healthcare Workers in a Intensive Care Unit by Using PBP2a Rapid Kit and Direct Coagulase Test (중환자실에 근무하는 의료인의 전비강에서 PBP2a Rapid Kit와 직접 Coagulase 검사를 이용한 Methicillin-resistant Staphylococcus aureus의 검출)

  • Hong, Seung-Bok;Shin, Kyung-A;Son, Jae-Cheol;Shin, Seob-Kyeong
    • Korean Journal of Clinical Laboratory Science
    • /
    • v.42 no.2
    • /
    • pp.86-91
    • /
    • 2010
  • We evaluated the performance of a novel screening test, PBP2a MRSA rapid kit (Dinona Inc., Iksan, Korea), for methicillin-resistant Staphylococcus aureus (MRSA) based on a immunochromatographic assay. The test is able to detect penicillin-binding protein 2a (PBP2a) using the nasal specimens from health care workers. The nasal specimens were obtained from 69 healthcare workers and were incubated in enrichment broth followed eight hours incubatin in BHI with cefoxitin $4{\mu}g/mL$. These broth were tested by PBP2a Rapid Kit. The enrichment broths were also directly tested for tube coagulase using the conventional identification method. 19 of 22 MRSA showed positive results by PBP2a rapid test and direct coagulase test (the sensitivity for detection of MRSA, 86.36%). While, 8 of 47 non-MRSA showed false positive results for the two tests. All of the 8 non-MRSA which showed false positive were co-colonizing isolates with MRCNS and MSSA. In addition, 46 of 49 methicillin-resistant staphylococci (MRS) showed positive results for PBP2a MRSA rapid kit (the sensitivity for detection of MRS, 93.8%), and all of 20 non-MRS showed negative results (specificity, 100%). The combination of PBP2a MRSA rapid kit and direct coagulase test showed the good sensitivity for detection of MRSA from anterior nares but frequently showed false positive results from the co-colonizing carrier with MRCNS and MSSA.

  • PDF

Comaprison of Six Serological Methods for the Diagnesis of Bovine Brucellosis (브루셀라병(病) 검색(檢索)에 사용(使用)되는 여러가지 혈청진단법(血淸診斷法)의 비교연구(比較硏究))

  • Kim, Keum-Hwa;An, Soo-Hwan;Park, Yong-Ho;Kim, Dong-Sung
    • Korean Journal of Veterinary Research
    • /
    • v.22 no.2
    • /
    • pp.149-153
    • /
    • 1982
  • Results obtained from six secological tests for diagnosing bovine brucellosis-standard plate agglutination test (SPT), standard tube agglutination test(STT), complement fixation test(CFT), Rivanol test (RT), agar gel precipitation test (AGP) and counterimmunoelectrophoresis(CIEP) were compared using 38 sera from brucella reactors and 222 sera from dairy and beef cattle in field. The SPT gave 1.6% apparent false negative reactions and 15.4% apparent false positive reactions when compared with STT which is an official test for bovine brucellosis in this country. The distribution of antibody titers determined by STT showed that 37.5% of 38 reactors had antibody titers ranging from 100 to 200, and the remaining 62.5% had antibody titers of 400 or higher. when 38 reactor judged by STT were tested by CFT and RT, 32 cattle(82.4%) were positive by CFT and 33 cattle (86.8%) were positive by RT, respectively. This results suggest that RT is comparable to CFT in the diagnosis of bovine brucellosis. The results also indicated that both AGP and CIEP were insensitive to detect brucella infection in cattle.

  • PDF

Urinalysis: The Usefulness and Limitations of Urine Dipstick Testing (요검사: 요시험지봉 검사의 유용성과 한계)

  • Han, Tae Hee
    • Childhood Kidney Diseases
    • /
    • v.17 no.2
    • /
    • pp.42-48
    • /
    • 2013
  • The urinalysis is an essential part of the diagnostic work-up for kidney disease and other renal system disorders. The dipstick test allows rapid and simultaneous chemical analyses of urine, including factors such as pH, specific gravity, protein, glucose, ketones, occult blood, bilirubin, urobilinogen, nitrite, and leukocyte-esterase. The chemical reactions on dipstick are complicated and can be affected by oxidizing, reducing, and discoloring substances in the urine. Therefore, false positive and false negative results are common in dipstick testing. To obtain reliable results with the dipstick, it is necessary to collect urine cleanly and examine the urine carefully. It is mandatory to clearly understand the principles of dipstick testing to evaluate abnormal findings. If the urine dipstick results suggest hematuria, proteinuria, or urinary tract infection, microscopy of the urine should be performed to confirm the findings.

Delamination identification of laminated composite plates using measured mode shapes

  • Xu, Yongfeng;Chen, Da-Ming;Zhu, Weidong;Li, Guoyi;Chattopadhyay, Aditi
    • Smart Structures and Systems
    • /
    • v.23 no.2
    • /
    • pp.195-205
    • /
    • 2019
  • An accurate non-model-based method for delamination identification of laminated composite plates is proposed in this work. A weighted mode shape damage index is formulated using squared weighted difference between a measured mode shape of a composite plate with delamination and one from a polynomial that fits the measured mode shape of the composite plate with a proper order. Weighted mode shape damage indices associated with at least two measured mode shapes of the same mode are synthesized to formulate a synthetic mode shape damage index to exclude some false positive identification results due to measurement noise and error. An auxiliary mode shape damage index is proposed to further assist delamination identification, by which some false negative identification results can be excluded and edges of a delamination area can be accurately and completely identified. Both numerical and experimental examples are presented to investigate effectiveness of the proposed method, and it is shown that edges of a delamination area in composite plates can be accurately and completely identified when measured mode shapes are contaminated by measurement noise and error. In the experimental example, identification results of a composite plate with delamination from the proposed method are validated by its C-scan image.

Pragmatic Strategies of Self (Other) Presentation in Literary Texts: A Computational Approach

  • Khafaga, Ayman Farid
    • International Journal of Computer Science & Network Security
    • /
    • v.22 no.2
    • /
    • pp.223-231
    • /
    • 2022
  • The application of computer software into the linguistic analysis of texts proves useful to arrive at concise and authentic results from large data texts. Based on this assumption, this paper employs a Computer-Aided Text Analysis (CATA) and a Critical Discourse Analysis (CDA) to explore the manipulative strategies of positive/negative presentation in Orwell's Animal Farm. More specifically, the paper attempts to explore the extent to which CATA software represented by the three variables of Frequency Distribution Analysis (FDA), Content Analysis (CA), and Key Word in Context (KWIC) incorporate with CDA decipher the manipulative purposes beyond positive presentation of selfness and negative presentation of otherness in the selected corpus. The analysis covers some CDA strategies, including justification, false statistics, and competency, for positive self-presentation; and accusation, criticism, and the use of ambiguous words for negative other-presentation. With the application of CATA, some words will be analyzed by showing their frequency distribution analysis as well as their contextual environment in the selected text to expose the extent to which they are employed as strategies of positive/negative presentation in the text under investigation. Findings show that CATA software contributes significantly to the linguistic analysis of large data texts. The paper recommends the use and application of the different CATA software in the stylistic and corpus linguistics studies.