Feature Engineering Using File Layout for Malware Detection

Malware detection on binary executables provides a high availability to even binaries which are not disassembled or decompiled. However, a binary-level approach could cause ambiguity problems. In this paper, we propose a new feature engineering technique that use minimal knowledge about the internal layout on a binary. The proposed feature avoids the ambiguity problems by integrating the information about the layout with structural entropy. The experimental results show that our feature improves accuracy and F1-score by 3.3% and 0.07, respectively, on a CNN based malware detector with realistic benign and malicious samples.Comment: 2pages, no figures, This manuscript was presented in the poster session of The Annual Computer Security Applications Conference (ACSAC) 202

A study on factors affecting the safety zone in ship-to-ship LNG bunkering

The objective of this paper is to examine the characteristics of leaked-gas dispersion in ship-to-ship liquefied natural gas (LNG) bunkering, thereby providing an insight towards determining the appropriate level of safety zones. For this purpose, parametric studies are undertaken in various operational and environmental conditions, with varying geometry of the ships, gas leak rate, wind speed and wind direction. The study applies computational fluid dynamics (CFD) simulations for case-specific scenarios where a hypothetical LNG bunkering ship with a capacity of 5100 m3 in tank space is considered to refuel two typical types of large ocean-going vessels: an 18,000 TEU container ship and a 319,000 DWT very large crude oil carrier. It is found that wind speed, wind direction, ship geometry and loading condition are important parameters affecting the extent of safety zones in addition to gas leak rate and leak duration. Details of the computations and discussions are presented

Comparison of usefulness of clinical diagnostic criteria for hepatocellular carcinoma in a hepatitis B endemic area

Background/AimsWe compared the accuracy and usefulness of clinical diagnostic criteria for hepatocellular carcinoma in a hepatitis B virus (HBV)-endemic area.MethodsWe reviewed the medical records of 355 patients who had undergone liver resection or biopsy at our institution between January 2008 and December 2009. These patients were reevaluated using four noninvasive diagnostic criteria for hepatocellular carcinoma proposed by the European Association for the Study of the Liver (EASL), the American Association for the Study of Liver Diseases (AASLD), the Korean Liver Cancer Study Group and the National Cancer Center (KLCSG/NCC), and National Comprehensive Cancer Network (NCCN) guidelines.ResultsThe overall sensitivity was highest using the KLCSG/NCC criteria (79.8%), followed by the AASLD (51.5%), EASL (38.4%), and NCCN (10.1%; P<0.001) criteria, whereas the specificity (84.5-98.3%) and positive predictive value (96.2-98.3%) were similar for all of the criteria. The KLCSG/NCC criteria had an acceptable false-positive rate and the highest sensitivity among all of the patients, including those positive for HBsAg, those without liver cancer, and those with a tumor of at least 2 cm.ConclusionsThe KLCSG/NCC and AASLD criteria exhibited the highest sensitivity, and all four guidelines had a high specificity among all of the patients. Based on the sensitivity and false-positive rate, the KLCSG/NCC criteria was the most useful in the majority of patients. Inclusion of HBV infection in the clinical diagnostic criteria for hepatocellular carcinoma would be reasonable and may lead to an improvement in the sensitivity, with acceptable false-positive rates, in HBV-endemic areas

A clinical predictor of varices and portal hypertensive gastropathy in patients with chronic liver disease

Background/AimsThe aim of this study was to identify the parameters that could noninvasively predict the presence of esophageal/gastric varices and portal hypertensive gastropathy (PHG) in patients with chronic liver disease (CLD), and to determine the accuracy of those parameters.MethodsWe retrospectively analyzed 232 patients with CLD who underwent both upper endoscopy and liver CT within an interval of 3 months. The multidimensional index (M-Index) for spleen volume was obtained from the multiplication of splenic length, width, and thickness, as measured by computer tomography.ResultsThe multivariate analysis revealed that platelet, albumin, and M-Index were independently associated with the presence of varices and PHG. We combined three independent parameters, and developed a varices and portal hypertensive gastropathy (VAP) scoring system (=[platelet count (/mm3)×albumin (g/dL)]/[M-Index (cm3)]). The area under the receiver operating characteristic curve of the VAP score was 0.850 (95% confidence interval, 0.801-0.899). The VAP cut-off value of 861 had a sensitivity of 85.3%, a positive likelihood ratio of 3.17, and a negative predictive value of 86.4%. For predicting high-risk lesions for bleeding, with a cut-off value of 861 the sensitivity was 92.0%, the positive likelihood ratio was 2.20, and the negative predictive value was 96.4%.ConclusionsThe VAP score can predict the presence of varices and PHG in patients with CLD and may increase the cost-benefit of screening endoscopy in the clinical practice setting. A prospective validation study is necessary in the future

Rescue therapy with adefovir in decompensated liver cirrhosis patients with lamivudine-resistant hepatitis B virus

Background/AimsAdefovir dipivoxil (ADV) is a nucleotide analogue that is effective against lamivudine-resistant hepatitis B virus (HBV). The aim of this study was to determine the long-term clinical outcomes after ADV rescue therapy in decompensated patients infected with lamivudine-resistant HBV.MethodsIn total, 128 patients with a decompensated state and lamivudine-resistant HBV were treated with ADV at a dosage of 10 mg/day for a median of 33 months in this multicenter cohort study.ResultsFollowing ADV treatment, 86 (72.3%) of 119 patients experienced a decrease in Child-Pugh score of at least 2 points, and the overall end-stage liver disease score decreased from 16±5 to 14±10 (mean ± SD, P<0.001) during the follow-up period. With ADV treatment, 67 patients (56.3%) had undetectable serum HBV DNA (detection limit, 0.5 pg/mL). Virologic breakthrough occurred in 38 patients (36.1%) and 9 patients had a suboptimal ADV response. The overall survival rate was 89.9% (107/119), and a suboptimal response to ADV treatment was associated with both no improvement in Child-Pugh score (≥2 points; P=0.001) and high mortality following ADV rescue therapy (P=0.012).ConclusionsThree years of ADV treatment was effective and safe in decompensated patients with lamivudine-resistant HBV

Transarterial chemoembolization versus resection for intermediate-stage (BCLC B) hepatocellular carcinoma

Background/Aims: Several studies have suggested that surgical resection (SR) can provide a survival benefit over transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC) at the intermediate stage according to the Barcelona Clinic Liver Cancer (BCLC) staging system. However, the criteria for SR remain to be determined. This study compared the long-term outcome of intermediate-stage HCC patients treated by either TACE or SR as a primary treatment modality, with the aim of identifying the patient subgroup that gained a survival benefit by either modality. Methods: In total, 277 BCLC intermediate-stage HCC patients treated by either TACE (N=225) or SR (N=52) were analyzed. Results: The overall median survival time was significantly better for SR than TACE (61 vs. 30 months, P=0.002). Decision-tree analysis divided patients into seven nodes based on tumor size and number, serum alpha-fetoprotein (AFP) level, and Child-Pugh score, and these were then simplified into four subgroups (B1–B4) based on similarities in the overall hazard rate. SR provided a significant survival benefit in subgroup B2, characterized by ‘oligo’ (2–4) nodules of intermediate size (5–10 cm) when the AFP levels was <400 ng/ml, or ‘oligo’ (2–4) nodules of small to intermediate size (<10 cm) plus a Child-Pugh score of 5 when the AFP level was ≥400 ng/mL (median survival 73 vs. 28 months for SR vs. TACE respectively; P=0.014). The survival rate did not differ significantly between SR and TACE in the other subgroups (B1 and B3). Conclusion: SR provided a survival benefit over TACE in intermediate-stage HCC, especially for patients meeting certain criteria. Re-establishing the criteria for optimal treatment modalities in this stage of HCC is needed to improve survival rates

Long-term Treatment Outcomes for Autoimmune Hepatitis in Korea

Immunosuppressive therapy can improve clinical, biochemical and histological features and considerably prolong survival in patients with autoimmune hepatitis. Although ethnicity may affect disease severity and presentation, the long-term outcome of immunosuppression in Korean populations is unknown. This study was aimed to assess the efficacy of immunosuppressive therapy and determine the prognosis of autoimmune hepatitis in Korean populations. We reviewed the medical records of 86 patients diagnosed as having autoimmune hepatitis at the Samsung Medical Center between 1994 and 2008. Seventy-two (83.7%) patients reached remission after a median treatment duration of 3.5 months (range 1 to 44 months). Attempts to withdraw medications were made in 24 cases after the median treatment duration of 36 months (median 6 to 125 months). Thirteen of 24 (54.1%) patients relapsed after treatment withdrawal. Of the 86 patients, 6 (7.2%) experienced disease progression and the overall 5-and 10-yr progression-free survival rates were 91.2% and 85.5%, respectively. In conclusion, immunosuppressive therapy for autoimmune hepatitis results in a favorable rate of remission and excellent progression-free survival, but the relapse rate after treatment withdrawal is high. This suggests that long-term immunosuppressive therapy may be particularly important for treatment of Korean patients

Clinical outcomes of balloon-occluded retrograde transvenous obliteration for the treatment of gastric variceal hemorrhage in Korean patients with liver cirrhosis: a retrospective multicenter study

Background/AimsThis study evaluated the clinical outcomes of balloon-occluded retrograde transvenous obliteration (BRTO) for the treatment of hemorrhage from gastric varices (GV) in Korean patients with liver cirrhosis (LC).MethodsWe retrospectively analyzed data from 183 LC patients who underwent BRTO for GV bleeding in 6 university-based hospitals between January 2001 and December 2010.ResultsOf the 183 enrolled patients, 49 patients had Child-Pugh (CP) class A LC, 105 had CP class B, and 30 had CP class C at the time of BRTO. BRTO was successfully performed in 177 patients (96.7%). Procedure-related complications (e.g., pulmonary thromboembolism and renal infarction) occurred in eight patients (4.4%). Among 151 patients who underwent follow-up examinations of GV, 79 patients (52.3%) achieved eradication of GV, and 110 patients (72.8%) exhibited marked shrinkage of the treated GV to grade 0 or I. Meanwhile, new-appearance or aggravation of esophageal varices (EV) occurred in 54 out of 136 patients who underwent follow-up endoscopy (41.2%). During the 36.0±29.2 months (mean±SD) of follow-up, 39 patients rebled (hemorrhage from GV in 7, EV in 18, nonvariceal origin in 4, and unknown in 10 patients). The estimated 3-year rebleeding-free rate was 74.8%, and multivariate analysis showed that CP class C was associated with rebleeding (odds ratio, 2.404; 95% confidence-interval, 1.013-5.704; P=0.047).ConclusionsBRTO can be performed safely and effectively for the treatment of GV bleeding. However, aggravation of EV or bleeding from EV is not uncommon after BRTO; thus, periodic endoscopy to follow-up of EV with or without prophylactic treatment might be necessary in LC patients undergoing BRTO