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Purpose: To perform real-time quantitative measurements of penile rigidity for patients with erectile dysfunction (ED) using shear-wave elastography (SWE). Materials and Methods: A total of 92 patients with clinically diagnosed ED filled out an abridged five-item version of the International Index of Erectile Function (IIEF-5) questionnaire and underwent SWE as well as penile color Doppler ultrasound (CDUS) after intracavernosal injection for penile erection. Elasticity measurements were repeated on two sites of the corpus cavernosum (central and peripheral elasticity of corpus cavernosum [ECC]) and the glans penis during the erection phase. Correlations between penile elasticity and rigidity scores or IIEF-5 were evaluated statistically. Penile elasticity was also compared with the ED types based on CDUS. Results: The mean age of all patients was 53.5±13.4 years, and the mean IIEF-5 score was 9.78±5.01. The rigidity score and central ECC value demonstrated a significant correlation (r=-0.272; 95% confidence interval: -0.464 to -0.056; p=0.015). The IIEF-5 score was not significantly correlated with penile elasticity. Vascular ED patients showed significantly higher central ECC values than nonvascular ED patients (p

Background and ObjectiveTo compare the incidence of febrile urinary tract infection (UTI) and bacterial identification between patients with orthotopic neobladder (ONB) and ileal conduit (IC). Materials and MethodsData of 164 patients who underwent radical cystectomy with ONB and IC for bladder cancer between January 2009 and January 2018 at our institution were analyzed. Febrile UTI observed was listed and subsequently compared. Incidence of febrile UTI, clinicopathological characteristics, and microorganisms identified were reported at 3 months interval; and preoperative predictors of febrile UTI were evaluated with Cox regression analysis. Patients were divided into ONB and IC. ResultsThe study cohort included 52 patients with ONB and 112 patients with IC. Febrile UTI was diagnosed in 49 (29.9%) patients. Compared to IC group, ONB group had significantly higher incidence of young age (p=0.00), lower cancer stage (p=0.013), longer hospital stay (p=0.049), longer operation time (p=0.00), and higher incidence of febrile UTI within the first 3 months after surgery (p=0.006). On univariable and multivariable analysis, factors associated with significantly increased febrile UTI risk were diabetes (odds ratio [OR]: 4.52; p=0.002) and ONB diversion (OR: 1.27; p=0.031). Forty-four (89.8%) patients were culture positive. However, significant difference in microorganisms was not detected between patients who under-went ONB or IC diversion. ConclusionDiabetes and ONB diversion were associated with higher risk symptomatic UTI following radical cystectomy.

Given the explosive growth of information technology and the development of computer vision with convolutional neural networks, wildfire field data information systems are adopting automation and intelligence. However, some limitations remain in acquiring insights from data, such as the risk of overfitting caused by insufficient datasets. Moreover, most previous studies have only focused on detecting fires or smoke, whereas detecting persons and other objects of interest is equally crucial for wildfire response strategies. Therefore, this study developed a multilabel classification (MLC) model, which applies transfer learning and data augmentation and outputs multiple pieces of information on the same object or image. VGG-16, ResNet-50, and DenseNet-121 were used as pretrained models for transfer learning. The models were trained using the dataset constructed in this study and were compared based on various performance metrics. Moreover, the use of control variable methods revealed that transfer learning and data augmentation can perform better when used in the proposed MLC model. The resulting visualization is a heatmap processed from gradient-weighted class activation mapping that shows the reliability of predictions and the position of each class. The MLC model can address the limitations of existing forest fire identification algorithms, which mostly focuses on binary classification. This study can guide future research on implementing deep learning-based field image analysis and decision support systems in wildfire response work.

Unsteady turbulent flow simulations were performed based on the Reynolds-averaged Navier–Stokes (RANS) equations to investigate flow oscillation due to three-dimensional (3D) configuration of a Mach 1.5 supersonic open cavity flow with a length-to-depth ratio of 3. Two-dimensional (2D) and 3D unsteady simulation results were analyzed and compared with experimental data and Rossiter’s empirical prediction data. The three-dimensional cavity width-to-depth ratio (W/D) was 1, 3.8 and 7.6. Computational results indicated that pressure oscillation in the 2D flow was generated by a single-flow structure, whereas a multiple-flow structure generated multiple oscillation peaks in the 3D flow. The flow structure in the 3D cavity was investigated. For the 2D flow case, the cavity internal pressure wave was directly synchronized with the free shear layer. In the 3D flow case, an unstable spanwise flow due to the sidewall was observed. This spanwise fluctuation produced additional pressure oscillations coupled with the streamwise internal pressure wave. The numerical results indicate that the spanwise flow reduces the propagation speed of the internal pressure waves and the intensity of the corresponding pressure fluctuation.

Flapping wing micro-air vehicles are biologically inspired by nature flyers, specifically insects and birds. Specifically, insect wings generally consist of veins and membrane components. In this study, a structural analysis considering the vein/membrane components of an insect-like flapping wing is presented. Co-rotational (CR) finite elements are adopted in order to consider the complex wing configuration including both vein and membrane. The CR beam elements with warping degrees of freedom are employed for veins and CR shell elements for the wing membrane. The present structural analysis is verified against the analytical results obtained by an existing software, and it is validated by comparison to existing results from the literature. A fluid–structure interaction analysis is then performed. In the procedure, an aerodynamic analysis based on three-dimensional preconditioned Navier–Stokes equations is employed. Finally, a comparative study with respect to the structural characteristics is conducted. As a result, an efficiency of the present structural analysis is confirmed by comparing with the existing software. It is found that the present FSI results are in good agreement with the existing experimental and numerical results. Moreover, the passive wing twist may have a significant influence on the hover performance.

In this paper, we present a computational aeroelastic analysis of flexible flapping wings in the vicinity of solid walls. The wall effects change the aerodynamic forces and moments of the wings, and thus the aeroelastic behavior. The numerical simulation is carried out using a fluid–structure interaction framework by coupling the computational fluid dynamics and computational structural dynamics. A preconditioned Navier–Stokes solver based on a finite volume method is used for the aerodynamic analysis. The structural analysis is performed using a nonlinear structural model based on a geometrically exact beam formulation. The method is validated using previous numerical and experimental results. The aeroelastic characteristics of the flexible wings with and without the walls are computed and compared.

Purpose This study aimed to develop a multi-channel near-infrared spectroscopy (NIRS) and ultrasonography (USG) fusion imaging system for imaging prostate cancer and to verify its diagnostic capability by applying the hybrid imaging system to a prostate cancer phantom. Methods A multi-channel NIRS system using the near-infrared 785-nm wavelength with 12 channels and four detectors was developed. After arranging the optical fibers around a USG transducer, we performed NIRS imaging and grayscale USG imaging simultaneously. Fusion imaging was obtained by processing incoming signals and the spatial reconstruction of NIRS, which corresponded with grayscale USG acquired at the same time. The NIRS-USG hybrid system was applied to a silicone-based optical phantom of the prostate gland containing prostate cancer to verify its diagnostic capability qualitatively. Results The NIRS-USG hybrid imaging system for prostate cancer imaging simultaneously provided anatomical and optical information with 2-dimensional registration. The hybrid imaging system showed more NIR attenuation over the prostate cancer model than over the model of normal prostate tissue. Its diagnostic capability to discriminate a focal area mimicking the optical properties of prostate cancer from the surrounding background mimicking the optical properties of normal prostate tissue was verified by applying the hybrid system to a silicone-based optical phantom of prostate cancer. Conclusion This study successfully demonstrated that the NIRS-USG hybrid system may serve as a new imaging method for improving the diagnostic accuracy of prostate cancer, with potential utility for future clinical applications.

Ultrasonography is effective for imaging superficial organs, such as the scrotum. Using a high-frequency transducer, ultrasonography can identify the location and characteristics of scrotal lesions with high accuracy. The primary role of ultrasound (US) in the evaluation of a scrotal mass is to determine if it is intratesticular or extratesticular. Additional clinical information and other imaging options may be needed to diagnose benign tumors and pseudo-tumors. MRI is an effective problem-solving tool in cases with nondiagnostic US findings. CT is helpful for staging testicular cancer and localizing undescended testis. This review covers the imaging features of testicular and extratesticular tumors.

At the foundation of every network security architecture lies the premise that formulated network flow policies are reliably deployed and enforced by the network infrastructure. However, software-defined networks (SDNs) add a particular challenge to satisfying this premise, as for SDNs the flow pol-icy implementation spans multiple applications and abstraction layers across the SDN stack. In this paper, we focus on the question of how to automatically identify cases in which the SDN stack fails to prevent policy inconsistencies from arising among these components. This question is rather essential, as when such inconsistencies arise the implications to the security and reliability of the network are devastating. We present AudiSDN, an automated fuzz-testing framework designed to formulate test cases in which policy inconsistencies can arise in OpenFlow networks, the most prevalent SDN protocol used today. We also present results from applying AudiSDN to two widely used SDN controllers, Floodlight and ONOS. In fact, our test results have led to the filing of 3 separate CVE reports. We believe that the approach presented in this paper is applicable to the breadth of OpenFlow platforms used today, and that its broader usage will help to address a serious but yet understudied pragmatic concern.

Wing flexibility affects the flight performance of flapping-wing micro air vehicles. In this paper, we present a computational approach for the aeroelastic analysis of realistic insect-like flexible flapping wings with hovering and forward-flight modes. A three-dimensional preconditioned Navier–Stokes solver is used with a deforming mesh technique for the aerodynamic analysis of a flapping wing. For the structural analysis, co-rotational (CR) finite elements and CR shell elements are used. As seen from the numerical analysis, wing flexibility leads to thrust increments with the increasing flapping frequency. The advance ratio, however, is the cause of the thrust decrease for flexible flapping wings with high flapping-frequency motions.

The RANS equations are widely used to analyze complex flows over aircraft. The equations require a turbulence model for turbulent flow analyses. A suitable turbulence must be selected for accurate predictions of aircraft aerodynamic characteristics. In this study, numerical analyses of three-dimensional aircraft are performed to compare the results of various turbulence models for the prediction of aircraft aerodynamic characteristics. A 3-D RANS solver, MSAPv, is used for the aerodynamic analysis. The four turbulence models compared are the Sparlart–Allmaras (SA) model, Coakley’s $$q-\omega $$ model, Huang and Coakley’s $$k-\varepsilon $$ model, and Menter’s $$k-\omega $$ SST model. Four aircrafts are considered: an ARA-M100, DLR-F6 wing–body, DLR-F6 wing–body–nacelle–pylon from the second drag prediction workshop, and a high wing aircraft with nacelles. The CFD results are compared with experimental data and other published computational results. The details of separation patterns, shock positions, and $$C_{p}$$ distributions are discussed to find the characteristics of the turbulence models.

Emerging software defined network (SDN) stacks have introduced an entirely new attack surface that is exploitable from a wide range of launch points. Through an analysis of the various attack strategies reported in prior work, and through our own efforts to enumerate new and variant attack strategies, we have gained two insights. First, we observe that different SDN controller implementations, developed independently by different groups, seem to manifest common sets of pitfalls and design weakness that enable the extensive set of attacks compiled in this paper. Second, through a principled exploration of the underlying design and implementation weaknesses that enables these attacks, we introduce a taxonomy to offer insight into the common pitfalls that enable SDN stacks to be broken or destabilized when fielded within hostile computing environments. This paper first captures our understanding of the SDN attack surface through a comprehensive survey of existing SDN attack studies, which we extend by enumerating 12 new vectors for SDN abuse. We then organize these vulnerabilities within the well-known confidentiality, integrity, and availability model, assess the severity of these attacks by replicating them in a physical SDN testbed, and evaluate them against three popular SDN controllers. We also evaluate the impact of these attacks against published SDN defense solutions. Finally, we abstract our findings to offer the research and development communities with a deeper understanding of the common design and implementation pitfalls that are enabling the abuse of SDN networks.

Purpose To evaluate the clinical safety and natural history of active surveillance (AS) for incidentally diagnosed small renal mass (SRM). Materials and methods We analyzed prospective data for patients who underwent AS for SRM. From 2010 to 2016, 37 SRMs of less than 3 cm were registered. Computed tomography (CT) and magnetic resonance imaging were used for initial diagnosis and CT, ultrasonography, and chest CT were performed at 6-month intervals. If there was no change in size during 2 years, follow-ups were performed annually. If the growth rate was more than 0.5 cm/y, if the diameter was more than 4 cm, or if clinical progression was observed, we regarded it as progression of SRM and recommended active treatment. We compared the growth rate and clinical course of SRM between patients who remained on surveillance and those who had progressed disease. Results The mean age was 63 years (range, 30-86 years) and the mean diameter was 1.8 cm (range, 0.6-2.8 cm) at diagnosis. The mean follow-up period was 27.3 months (range, 6-80 months) and the average growth rate was 0.2 cm/y (range, 0-1.9 cm/y). Six patients (16.2%) showed progression of SRM. Three patients wanted continuous observation, and partial nephrectomy was performed on 3 other patients. None of the patients had clinical progression, including metastasis. Conclusions We could delay active treatment for patients with an SRM with scheduled surveillance if the SRM grew relatively slowly. If more long-term AS results are documented for more patients, AS could be an alternative treatment modality for SRM.

PURPOSE To determine the efficacy of cognitive targeted prostate biopsy using biparametric magnetic resonance imaging (b-MRI) for patients with prostate-specific antigen levels under 10 ng/mL. MATERIALS AND METHODS We reviewed data from 123 consecutive patients who underwent cognitive targeted prostate biopsy using prostate MRI. Of these patients, the first 55 underwent prostate biopsy using multiparametric MRI (mp-MRI), and the remaining 68 underwent prostate biopsy using b-MRI. For b-MRI, we generated T2 weighted axial imaging and diffusion-weighted imaging sequences. We found that 62 of the 123 men had suspicious lesions on MRI (32 of the 55 men in the mp-MRI group and 30 of the 68 men in the b-MRI group). We compared the prostate cancer detection rates and the proportions of clinically significant prostate cancer between the different MRI sequences. RESULTS Between the two MRI groups, there were no statistically significant differences in prostate cancer detection rate and proportions of clinically significant prostate cancer (41.8% vs. 30.9%, p=0.208 and 82.6% vs. 76.2%, p=0.598). Among the 62 men who had suspicious lesions on MRI, the prostate cancer detection rates were 62.5% and 63.3% (p=0.709) in the mp-MRI and b-MRI groups, respectively, and the proportions of clinically significant prostate cancer were 95.0% and 84.2% (p=0.267). CONCLUSION Prostate biopsy using b-MRI showed similar performance to that using mp-MRI for detecting prostate cancer and clinically significant prostate cancer. Considering the satisfactory performance and cost effectiveness of b-MRI, this technique could be a good option for obtaining intraprostatic information for first round prostate biopsy.

플랫폼과 이탈방사체가 동적인 상태에 있는 교전 시나리오에서 지상 추적 레이다에 대한 이탈방사체의 재밍/기만 효과를 분석한다. 플랫폼의 운동과 주변 간섭 유동장에 따른 이탈방사체의 궤적을 6자 유도 운동 방정식을 이용하여 해석한다. 실제적인 교전 시나리오에서 플랫폼과 이탈방사체의 운동 변화 및 이탈방사체의 RF 성능 변화에 따른 지상 추적레이다에 대한 재밍 성능을 분석하며, 효과적인 지상 추적 레이다 기만을 위한 이탈방사체의 재밍 영역을 도출한다.

Recent advance in flapping-wing MAVs has led to greater attention being paid to the interaction between the structural dynamics of the wing and its aerodynamics, both of which are closely related to the performance of a flapping wing. In this paper, an improved computational framework to simulate a flapping wing is developed. This framework is established by coupling a preconditioned Navier–Stokes solution and a co-rotational beam analysis with a restrained warping degree of freedom. Validation of the present framework is performed by a comparison with examples from either earlier analyses or experiments. Further, a numerical analysis of a wing under simultaneous pitching and plunging motion is examined. The results are compared with those obtained with a wing under pure plunging motion, in order to assess the additional motion effect within a spanwise flexible wing. The comparison shows different aerodynamic characteristics induced by the flexibility of the wing, which can be beneficial.

In this paper, a triangular planar element is developed for a geometrically nonlinear structural analysis, which includes the drilling degrees of freedom using a corotational framework. Based on the assumptions of a small degree of strain and large displacement, the corotational framework allows an accurate geometrically nonlinear structural analysis. The presently improved corotational framework accommodates in-plane rotational behavior (that is, the drilling degrees of freedom) by using the corotational framework corresponding to a solidlike planar element. It focuses on triangular planar elements that will be useful for three-dimensional analysis using a reduced number of degrees while targeting a structure with a complex geometry, such as a flapping wing. Regarding the present analysis, validation by solving both static and time-transient problems is conducted. The fluid–structure interaction framework is then developed by using the present structural analysis. During this validation procedure, the pr...

An effective time-domain aeroelastic framework for bridge deck flutters is presented based on a modified implicit coupling algorithm with grid deformation techniques. The grid deformation is accomplished by radial basis function interpolation as well as by the rigid movement of the initial grid. In this paper, for computational efficiency, a coupling frequency control technique is adopted for the implicit coupling algorithm. To verify the time-domain aeroelastic framework by using the grid deformation technique, the vortex-induced vibration of the cylinder and H-section bridge deck flutter are computed, and the results are compared with published results. The effect of the coupling frequency with the grid deformation technique is presented for the flutter analysis of the Great Belt East Bridge suspension girder section.

Background Transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC) frequently causes feeding artery stenosis or occlusion that may interfere with repeated treatment. Purpose To investigate the incidence and predictors of hepatic arterial damage (HAD) after drug-eluting bead-TACE (DEB-TACE) in comparison with conventional TACE (Conv-TACE). Material and Methods We retrospectively analyzed 54 patients who underwent DEB-TACE for HCC as an initial treatment with follow-up angiography and 54 patients who underwent Conv-TACE using doxorubicin-lipiodol mixture and gelfoam particles for comparison. HAD was evaluated after a single session of TACE and graded as follows: grade I, no significant wall irregularity; grade II, overt stenosis; grade III, occlusion. Results The incidence of HAD was significantly higher in the DEB-TACE group than the Conv-TACE group when analyzed per branch (odds ratio [OR], 6.36; P Conclusion The incidence and grade of HAD were higher after DEB-TACE compared to Conv-TACE with doxorubicin dose as a possible risk factor. HAD was independent of overall survival in both groups.

Purpose To develop and validate a deep learning system (DLS) for staging liver fibrosis by using CT images in the liver. Materials and Methods DLS for CT-based staging of liver fibrosis was created by using a development data set that included portal venous phase CT images in 7461 patients with pathologically confirmed liver fibrosis. The diagnostic performance of the DLS was evaluated in separate test data sets for 891 patients. The influence of patient characteristics and CT techniques on the staging accuracy of the DLS was evaluated by logistic regression analysis. In a subset of 421 patients, the diagnostic performance of the DLS was compared with that of the radiologist's assessment, aminotransferase-to-platelet ratio index (APRI), and fibrosis-4 index by using the area under the receiver operating characteristic curve (AUROC) and Obuchowski index. Results In the test data sets, the DLS had a staging accuracy of 79.4% (707 of 891) and an AUROC of 0.96, 0.97, and 0.95 for diagnosing significant fibrosis (F2-4), advanced fibrosis (F3-4), and cirrhosis (F4), respectively. At multivariable analysis, only pathologic fibrosis stage significantly affected the staging accuracy of the DLS (P = .016 and .013 for F1 and F2, respectively, compared with F4), whereas etiology of liver disease and CT technique did not. The DLS (Obuchowski index, 0.94) outperformed the radiologist's interpretation, APRI, and fibrosis-4 index (Obuchowski index range, 0.71-0.81; P ˂ .001) for staging liver fibrosis. Conclusion The deep learning system allows for accurate staging of liver fibrosis by using CT images. © RSNA, 2018 Online supplemental material is available for this article.

Purpose As endoscopic treatment for vesicoureteral reflux (VUR) has increased, secondary ureteral reimplantation (UR) after failure of endoscopic treatment has increased. We studied the clinical feature and efficacy of secondary UR after failure of endoscopic treatment compared with primary UR. Materials and methods Eighty-one children who had UR for VUR were enrolled. Charts were reviewed retrospectively for age, sex, grade of VUR before surgery, operative time, hospitalization period, postoperative complication, and success rate. Primary UR (group A, n=64) was compared with secondary UR after failed endoscopic treatment (group B, n=17). In group B, telephone survey for the satisfaction of endoscopic treatment and surgery was done. Results Mean age of each group was 49.6±37.1 and 56.6±22.5 months (p=0.236). There was no significant difference between each group in sex, mean operative time, postoperative transfusion, complication rate, and success rate. As telephone survey in group B, eleven responders preferred endoscopic treatment as primary treatment of VUR because it was a simple method and no hospitalization. Conclusions Secondary UR after failure of endoscopic treatment was similar to primary UR. Parents preferred endoscopic treatment as first line treatment for VUR in spite of the need for secondary UR after failure of endoscopic treatment.

We propose a numerical scheme to simulate the time-domain echo signals at tracking radar for a realistic scenario where an EAD (expendable active decoy) and an airborne target are both in dynamic states. On various scenarios where the target takes different maneuvers, the trajectories of the EAD ejected from the target are accurately calculated by solving 6-DOF (Degreeof-Freedom) equations of the motion for the EAD. At each sampling time of the echo signal, the locations of the EAD and the target are assumed to be fixed. Thus, the echo power from the EAD can be simply calculated by using the Friis transmission formula. The returned power from the target can be computed based on the pre-calculated scattering matrix of the target. In this paper, an IPO (iterative physical optics) method is used to construct the scattering matrix database of the target. The sinc function-interpolation formulation (sampling theorem) is applied to compute the scattering at any incidence angle from the database. A simulator is developed based on the proposed scheme to estimate the echo signals, which can consider the movement of the airborne target and EAD, also the scattering of the target and the RF specifications of the EAD. For applications, we consider the detection probability of the target in the presence of the EAD based on Monte Carlo simulation.

Software-defined networking (SDN) is being strongly considered as the next promising networking platform, and studies regarding SDN have been actively conducted accordingly. However, the security of SDN remains undefined and unknown when considering the enhancement of network security in SDN. In this paper, we verify whether SDN can enhance network security. Specifically, the idea of enabling security functions with diverse SDN features is explored thoroughly. In order to elucidate the feasibility of SDN-based security functions, we implement four types of security functions with SDN in Floodlight applications: (i) in-line mode security functions (e.g. firewalls and IPS), (ii) passive mode security functions (e.g. IDS), (iii) network anomaly detection functions (e.g. scan and DDoS detector), and (iv) advanced security functions (e.g. stateful firewall and reflector networks). Furthermore, we focus on discovering issues that might arise throughout the implementation of SDN-based security applications and discuss how these issues can be addressed. In order to appropriately prove the feasibility of the SDN-based security applications, we evaluate our Floodlight applications in real testbeds that consist of SDN-enabled switches and a number of physical hosts.

Purpose: This study was conducted to compare the accuracy of bi-parametric magnetic resonance imaging (bpMRI) with high b-value (b=1,000 s/mm2, b1000) diffusion-weighted imaging (DWI) to that of bpMRI with ultra-high b-value (b=1,800 s/mm2, b1800) DWI to detect clinically significant prostate cancer (csPCa). Materials and Methods: A total of 408 patients with suspected PCa were evaluated by bpMRI prior to biopsy. One reader retrospectively reviewed all images for confirmation of Prostate Imaging–Reporting and Data System (PI-RADS) score. Cognitive magnetic resonance/ultrasound fusion target biopsy was done for all visible lesions (PI-RADS 3–5). Systematic biopsy was done for all cases. The csPCa detection rates were compared according to the bpMRI protocol (with/without b1800 DWI) or PI-RADS score. The accuracy of PI-RADS score was estimated using receiver operating characteristics curve. The signal intensity (SI) ratio (visible lesion/surrounding background) was evaluated. Results: Among 164 men confirmed having PCa, 102 had csPCa (Gleason score≥7). Proportions of PI-RADS score 1–2/3/4/5 without b1800 DWI (n=133) and with b1800 DWI (n=275) were 19.5%/57.9%/15.8%/6.8% and 21.1%/48.7%/22.2%/8.0%, respectively. csPCa detection rates with/without b1800 DWI were 27.6%/19.5% (p=0.048), respectively. Areas under the curve of PI-RADS grading with/without b1800 DWI for csPCa detection were 0.885 and 0.705, respectively. The SI ratio in b1800 DWI was higher than that in b1000 DWI (p

Software-Defined Networking (SDN), which separates the control plane from the data plane and manages data planes in a centralized way, is now considered as a future networking technology, and many researchers and practitioners have dived into this area to devise new network applications, such new routing methods. Likewise, network security applications could be redesigned with SDN, and some pioneers have proposed several interesting network security applications with SDN. However, most approaches have just reimplemented some well-known network security applications, although SDN provides many interesting features, They didn’t effectively use them. To investigate if we can use SDN in realizing sophisticated network security applications, we have designed and implemented an advanced network security application, Reflectornet, which redirects malicious or suspicious network trials to other security monitoring points (e.g., honeypot). In addition, we have tested its performance and practicability in diverse angles. Our findings and some insights will encourage other researchers to design better or intelligent network security applications with SDN. 논문 14-39B-06-08 The Journal of Korea Information and Communications Society '14-06 Vol.39B No.06 http://dx.doi.org/10.7840/kics.2014.39B.6.397 397 First Author : KAIST Graduate School of Information Security, taejune.park@kaist.ac.kr, 학생회원 ° Corresponding Author : KAIST Graduate School of Information Security, claude@kaist.ac.kr, 정회원 * KAIST Graduate School of Information Security, lss365@kaist.ac.kr, 학생회원 논문번호:KICS2014-06-219, Received June 2, 2014; Revised June 18, 2014; Accepted June 18, 2014 The Journal of Korea Information and Communications Society '14-06 Vol.39B No.06

A general purpose aircraft mission performance analysis program has been developed. The program can be used in design mode or in analysis mode. Fuel weight for a given mission profile can be estimated when the design mode is chosen, while mission time or mission range for a given fuel can be estimated when the analysis mode is chosen. The mission analysis program is written with JAVA and includes GUI(Graphic User Interface) for users’ conveniences. With a proper combination of databases for propulsion, aerodynamics and weight, the program can be configured to compute the performance of any type of aircraft. The program is validated by comparing its results with the results of a well known performance analysis program by ADD(Agency for Defense Development)

In this paper, numerical simulations are performed on the lock-in phenomena of vortex induced vibration(VIV) of a two dimensional cylinder. A deforming grid as well as a rigidly moving grid are used to simulate the movement of the cylinder. The grid deformation is accomplished by the linear spring analogy. Converged solutions, which are obtained by controling the grid size and the non-dimensional time step, are used for comparison and validation of the analysis results. Moreover, the efficiency and the accuracy of the coupling methods for fluid-structure interaction are examined.

This paper presents the computations of the longitudinal and directional stability derivatives for the SDM(Standard Dynamic Model). The static and dynamic derivatives are evaluated at once using forced harmonic oscillations in the pitch and yaw directions. For the numerical simulations, a 3-D Euler solver that uses a dual time stepping method for unsteady time accurate simulations is applied. This work investigates the variation of the derivatives in terms of the Mach number and the several motion parameters. Good agreement of the pitch and yaw stability derivatives with previously published numerical results and experimental results are observed.

Realistic computations of flows induced by synthetic jets in multiple flow conditions are studied with an unsteady preconditioned Reynolds-averaged Navier–Stokes solver with deforming meshes. Deforming meshes suitable for structured grid systems are used to simulate the motion of diaphragms driven at a given frequency.With deforming meshes, a boundary-conditionmodel is not necessary for synthetic jet calculations. To obtain time-accurate solutions with a grid system under deformation, the geometric conservation law is employed. Numerical calculations of three cases of the Langley Research Center Workshop Computational Fluid Dynamics Validation of Synthetic Jets and Turbulent Separation Control workshop are carried out, and the computational results are compared with the experimental data. The results indicate the effectiveness of the current method in synthetic jet flow computations.

A computer program that can estimate static, dynamic stability and control derivatives using a subsonic-supersonic panel method is developed. The panel method uses subsonic-supersonic source and elementary horse shoe vortex distributions, and their strengths are determined by solving the boundary condition approximated with a thin body assumption. In addition, quasi-steady analysis on the body fixed coordinate system allows the estimation of damping coefficients of aircraft 3 axes. The code is validated by comparing the neutral point, roll and pitch damping of delta wings with published analysis results. Finally, the static, dynamic stability and control derivatives of F-18 are compared with experimental data as well as other numerical results to show the accuracy and the usefulness of the code. 초 록 아음속-초음속 패널법(panel method)을 이용하여 항공기의 정적 안정성 미계수와 동적 안정성 미계수 및 조종미계수를 예측할 수 있는 프로그램을 개발하였다. 사용된 코드는 아음속-초음속 소스(source)와 말굽 와류(elementary horse shoe vortex)의 분포를 사용하고, 그 분포의 크기는 얇은 물체 근사(thin body approximation)을 적용하여 간략히 한 경계 조건을 이용하여 계산하였다. 항공기에 부착된 물체 좌표계에서 준정상(quasi-steady) 해석 을 통해서 항공기 3축의 댐핑 계수를 예측하였다. 개발된 코드는 삼각날개(delta-wing)의 중립점(neutral point), 롤, 피치 댐핑 계수의 이론치와 비교하여 검증하였다. 마지막으로 F-18의 정적, 동적 안정성 미계수와 조종 미계수를 풍동 시험치와 계산치에 비교하여 개발 한 코드의 정확성과 유용성을 확인하였다.

This paper presents computations of the dynamic derivatives of three dimensional flight vehicle configurations using CFD. The pitch dynamic derivatives are computed from the pitch sinusoidal motion, while the roll damping is computed based on steady state calculation using a non-inertial frame method. The Basic Finner and the SDM(Standard Dynamic Model) are chosen for the benchmark tests against other numerical and experimental results. For the flow calculations, a 3-D Euler solver that can be run both on the non-inertial frame and on the inertial frame is developed. A dual-time stepping method is applied for the unsteady time accurate simulations. A good agreement of pitch-roll dynamic derivatives with previously published numerical results and the experimental results is observed.

This paper investigates the convergence characteristics of the modified artificial compressibility method proposed by Turkel. In particular, a focus is mode on the convergence characteristics due to variation of the preconditioning factor (αu) and the artificial compressibility ( β) in conjunction with an upwind method. For the investigations, a code using the modified artificial compressibility is developed. The code solves the axisymmetric incompressible Reynolds averaged Navier-Stokes equations. The cell-centered finite volume method is used in conjunction with Roe’s approximate Riemann solver for the inviscid flux, and the central difference discretization is used for the viscous flux. Time marching is accomplished by the approximated factorizationalternate direction implicit method. In addition, Menter’s k-ω shear stress transport turbulence model is adopted for analysis of turbulent flows. Inviscid, laminar, and turbulent flows are solved to investigate the accuracy of solutions and convergence behavior in the modified artificial compressibility method. The possible reason for loss of robustness of the modified artificial compressibility method with αu >1.0 is given.

In this study, fairing configurations for an aircraft are designed and the aerodynamic analyses of the fairings are performed to find the best choice for the aircraft. Fairings considered are wing-tip fairing and wing-body fairing. Wing alone analyses are done for the wing-tip faring selection, while wing-body-tail analyses are done for the wing-body fairing selection. A 3-D RANS solver with Menter`s SST turbulence model are used for the aerodynamic analyses. The effects on the drag of the aircraft are examined by comparing the analysis results with and without the farings.

Varicocelectomy is a management option for patients with painful varicocele. In this study, we assessed the effectiveness of varicocelectomy for painful varicocele and examined the factors that might be predictive of outcome. All patients who underwent a varicocelectomy for pain between February 2007 and July 2009 were included. A review of patient medical records was conducted; patient age, body mass index (BMI), grade, location of the varicocele, testicular volume, duration and quality of the pain (dull, dragging, throbbing or sharp) and surgical technique (inguinal versus subinguinal) were documented. All parameters were compared with the resolution of pain (complete, partial or failure). We followed up on 53 of 104 patients (51.0%). Complete postoperative resolution of pain was reported by 28 patients (52.8%), whereas 22 (41.5%) reported partial resolution. Only three patients (5.7%) reported failure. No relationship was observed between postoperative pain resolution and age, BMI, grade of varicocele, location of varicocele, ipsilateral testicular hypotrophy, quality of pain or surgical technique. The duration of pain before surgery was the only factor that correlated with postoperative pain resolution (univariate, P=0.004; multivariate, P=0.002). Our results indicate that varicocelectomy is an effective treatment for painful varicocele in properly selected patients, and that duration of pain before surgery may be predictive of outcome.

Purpose: The prognostic significance of perineural invasion by prostate cancer is debated. We investigated the association between perineural invasion and clinicopathological factors and the effect of perineural invasion on survival in patients with prostate cancer. Materials and Methods: A total of 361 patients with prostate cancer without any neoadjuvant therapies prior to surgery from 1999 to 2010 were analyzed retrospectively. Whole-mount sections of surgical specimens from all patients who underwent radical prostatectomy were evaluated. Positive perineural invasion was defined as infiltration of cancer cells in the perineurium or neural fascicles. The relationship of perineural invasion with clinicopathological features and prognosis of prostate cancer was studied. We also researched preoperative factors that were associated with perineural invasion. Results: Perineural invasion in a prostatectomy specimen (PNIp) was positive in 188 of 361 patients (52.1%). In the multivariate analysis of the preoperative variables, PNIp was related to the primary Gleason grade (p=0.020), the number of positive cores (p= 0.008), and the percentage of tumor cells in positive cores (p=0.021), but not to perineural invasion of a prostate biopsy. In the evaluation between PNIp and pathologic findings of the prostatectomy specimen, PNIp was related to the Gleason score (p=0.010), T-stage (p=0.015), and lymphovascular invasion (p=0.019). However, by multivariate analysis, the PNIp was not an independent prognostic factor of biochemical serum recurrence (p=0.364) or cancer-specific survival (p=0.726). Conclusions: PNIp was significantly related to biologically aggressive tumor patterns but was not a prognostic factor for biochemical serum PSA recurrence or cancer-specific survival in patients with prostate cancer.

Off-line 6-DOF simulation program for store separation analysis has been developed. The developed program enables to predict a trajectory of a store from the database which was constructed by wind tunnel testing or CFD analysis. The flow angle method was applied to the program for predicting aerodynamic coefficients from the database and the ejector forces and constraints were enabled to incorporate the equations of motion for computing the trajectory. Using the program, the trajectories were calculated and the results are compared with the CTS results.

Luxury sound is one of the most important sound qualities in a premium passenger car. Previous work has shown that, because of the effects of many different interior sounds, it is difficult to evaluate the luxury sound objectively by using only the A-weighted sound pressure level. The characteristics of such sound were systematically investigated and a new objective evaluation was proposed of the luxury sound quality index. This was developed by the systematic combination of the seven major interior sound quality indices based on path analysis. These sounds inside a passenger car were evaluated by the members of a luxury automotive club. Then, by using sound metrics (psychoacoustic parameters) and multiple regression, seven major interior sound quality indexes were developed. Multiple regression was used to model the correlation between objective and subjective evaluation. The newly developed luxury sound quality index can be applied to the objective evaluation of the seven premium passenger cars in a pilot car stage based on the customer preference.

A numerical procedure for aerodynamic load analysis of long span bridges is presented. The preconditioned Reynolds averaged Navier-Stokes equations are adopted to compute flows over the bridges. To capture the turbulent characteristics of the flows, two equation turbulence models, Coakley’s q − ω model and Menter’s k − ω SST model, are used to compute the turbulent viscosity. A dual time stepping method in conjunction with the AF-ADI method is used to advance the solution in time. A loosely coupled method of the preconditioned RANS equations with the turbulence model equations is employed for fast computation without losing numerical stability. The numerical method for the aerodynamic load analysis is verified against well-known benchmark problems. Aerodynamic loads of two real bridges are computed with the method to demonstrate the usefulness of the method.

A program package for store separation analysis, SAFESEP, has been developed. The package includes CTS system software, 3-Dimensional visualization software, off-line store trajectory software and aerodynamic database software. In this paper, we describe the functions and the capabilities of the store separation analysis program package.

Euler codes or Navier-Stokes codes for compressible flows suffer severe degradation in convergence as Mach number approaches zero. The convergence problem arose from the wide disparity in characteristic speeds can be solved using preconditioning methods without large modifications. In this paper, a preconditioned RANS(Reynolds Averaged Navier-Stokes) solver is developed for analysis of low Mach number flows. In order to validate the method, computational examples are chosen and the results are compared with the experimental data and the existing computed results showing a good accuracy and convergence characteristics for steady inviscid, laminar and turbulent flows at low Mach number.

Aerodynamic data measured in a wind tunnel has inevitable errors due to the presence of the wind tunnel walls. These unwanted interference effects must be corrected for the wall interference free aerodynamic data. Streamline curvature effects are caused by straightening of streamlines due to wind tunnel walls. Classical Glauert`s correction method that is a standard method for fixed wing aircraft is not suitable for rotary wing aircraft. In this paper, Heyson`s correction method of which wake model is compatible with rotors is used to correct the rotor shaft angle as well as the dynamic pressure. The results of Heyson`s method are compared with Glauert`s correction method.