Aerobic Copper-Promoted Oxidative Dehydrosulfurative Carbon-Oxygen Cross-Coupling of 3,4-Dihydropyrimidine-1: H -2-Thiones With Alcohols

An aerobic Cu-promoted oxidative dehydrosulfurative carbon-oxygen cross-coupling of 3,4-dihydropyrimidin-1H-2-thiones (DHPMs) with both aliphatic and aromatic alcohols is described. Together with the ready availability of DHPMs and both alcohols, the method furnishes facile access to biologically valuable 2-alkoxypyrimidines with rapid diversification

Privacy-preserving PKI design based on group signature

Nowadays, Internet becomes a part of our life. We can make use of numerous services with personal computer, Lap-top, tablet, smart phone or smart TV. These devices with network make us enjoy ubiquitous computing life. Sometimes, on-line services request us authentication or identification for access control and authorization, and PKI technology is widely used because of its security. However the possibility of privacy invasion will increase, if We’re identified with same certificate in many services and these identification data are accumulated. For privacy-preserving authentication or anonymous authentication, there have been many researches such as Group signatures, anonymous credentials, etc. Among these researches, group signatures are very practical Because they provide unlinkability and traceability as well as anonymity. In this paper, we propose a privacy-preserving PKI based on group signature, with which users’ privacy can be Kept in services. Because of traceability, their identities can be traced if they abuse anonymity such as cybercrime. Moreover, we will also discuss open issues for further studies

Autorotation flight control system

The present invention provides computer implemented methodology that permits the safe landing and recovery of rotorcraft following engine failure. With this invention successful autorotations may be performed from well within the unsafe operating area of the height-velocity profile of a helicopter by employing the fast and robust real-time trajectory optimization algorithm that commands control motion through an intuitive pilot display, or directly in the case of autonomous rotorcraft. The algorithm generates optimal trajectories and control commands via the direct-collocation optimization method, solved using a nonlinear programming problem solver. The control inputs computed are collective pitch and aircraft pitch, which are easily tracked and manipulated by the pilot or converted to control actuator commands for automated operation during autorotation in the case of an autonomous rotorcraft. The formulation of the optimal control problem has been carefully tailored so the solutions resemble those of an expert pilot, accounting for the performance limitations of the rotorcraft and safety concerns

Mesenteric extraskeletal osteosarcoma with telangiectatic features: a case report

<p>Abstract</p> <p>Background</p> <p>Extraskeletal osteosarcoma is a rare malignant mesenchymal tumor, with a predominant occurrence in the extremities. Only two cases of mesenteric extraskeletal osteosarcoma have been documented. We describe an unusual case of extraskeletal osteosarcoma with telangiectatic features occurring in the mesentery.</p> <p>Case presentation</p> <p>A 67-year-old male presented with blood-tinged stool of 1-month's duration. On colonoscopy, a solid mass was detected protruding from the colon wall. Computed tomography showed a 15 × 9.7 cm heterogeneously enhancing mass, with mottled calcification and a cystic portion, occupying the left upper quadrant of the abdominal cavity. Curative resection of the tumor was performed, and the excised tumor was composed of large multilocular cysts containing old hematomas and necrotic debris. The histology revealed an osteosarcoma showing osteoid formation and blood-filled spaces lined with atypical cells. Despite postoperative chemotherapy, he developed a recurrent peritoneal mass and multiple lung metastases 3 months postoperatively.</p> <p>Conclusion</p> <p>Given the rarity of cases of mesenteric extraskeletal osteosarcoma, its biologic behavior at this location remains to be determined. However, extraskeletal osteosarcoma with telangiectatic features is an uncommon entity to be recognized because of the possible fatal outcome related to the tumors.</p

Kinetics of cytokine expression in cirrhotic rats

AbstractBackgroundCytokines are involved in liver injury and cirrhosis and systemic and hepatic cytokine levels may help predict cirrhosis evolution. However, the relevant survey has not been performed.MethodsMale Sprague-Dawley rats (240–270g) received either common bile duct ligation (BDL, animal model of cholestatic liver injury) or sham operation (control). Five rats were sacrificed and liver and serum were collected from each in weeks 1, 2, 4, 6, 8 and 10 after surgery. Hepatic expression of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10) and transforming growth factor-β (TGF-β) were analyzed by immunohistochemial staining. The corresponding serum levels were measured by ELISA.ResultsCompared to the corresponding sham groups, hepatic expression of these cytokines in BDL rats was significantly and progressively enhanced during cirrhosis development. However, serum IFN-γ levels of BDL rats did not change significantly. Serum TNF-α of BDL rats increased gradually and reached a peak in week 6. Serum TGF-β level was elevated up to week 8, whereas IL-10 level decreased progressively until week 6.ConclusionCirrhosis development in BDL rats is associated with progressively enhanced expression of hepatic pro-inflammatory and anti-inflammatory cytokines, which is not in accord with the corresponding serum concentration. The circulating cytokine concentration may not totally reflect the hepatic expression level throughout the development of cirrhosis

블루투스 시스템에서의 저연산량 스펙트럼 센싱에 관한 연구

In this paper, we propose a complexity reduced spectrum sensing scheme for Bluetooth to avoid the interference from other communication devices in 2.4 GHz ISM band. By exploiting the spectrum characteristics of interference sources, the proposed scheme detects the availability of channels by comparing the power spectrum density (PSD) with a threshold. To reduce the implementation complexity, the PSD is calculated by means of fast Fourier transform and linear interpolation. The threshold for the detection is determined to maximize the detection probability. To further improve the transmission performance, the proposed scheme dynamically changes the channels by measuring the transmission performance. Finally, the performance of the proposed scheme is verified by computer simulation in the presence of WLANs in the ISM band.Seoul R&BS Progra

Orthogonal Muti-beam Techniques for Multi-user Diversity and Multiplexing Gain in Packet-based Wireless Systems

In this paper, we consider the use of orthogonal multiple beams (OMBs) to simultaneously achieve multi-user diversity and multiplexing gain in a packet-based wireless system. Previous schemes consider the use of a fixed number of OMBs according to the number of transmit antennas. However, unless the number of active users is sufficiently large, the use of multiple beams may not provide desired performance mainly due to the interference from other users signals, being even worse than the use of a single beam. To alleviate this problem, we consider the adjustment of the number of beams in use to maximize the spectral efficiency according to the operating condition. Simulation results show the validity of the proposed scheme

패킷 기반 무선 시스템에서 다중 직교 빔을 이용한 다중 안테나 송수신 기법

In this paper, we consider the use of multiple beams to simultaneously achieve both diversity and multiplexing gain in multi-user domain in multiple access systems. Orthogonal multiple beams are generated to provide the users with multiple channels at the same time, achieving multi-user diversity through each channel. However, when the number of active users is not large, the performance can significantly be affected by the interference from other users. To alleviate this problem, we propose a multi-beam scheme to adjust the number of beams according to the channel condition or the number of users.the Ministry of Information & Communications, Korea, under the Information Technology Research Center (ITRC) Support Progra

수신 상관정보를 이용한 상향링크 셀룰러 시스템에서의 사용자 스케줄링에 관한 연구

In this paper, we consider multi-user scheduling to maximize the ergodic capacity near the cell boundary in the uplink of cellular systems. The base station (BS) determines a user pair that can minimize the interference from other cells by exploiting the receive correlation matrices of users from adjacent BSs. The performance of the proposed scheme is verified by computer simulation. Simulation results show that the proposed multi-cell scheduling significantly increase the ergodic capacity near the cell boundary compared to conventional random user scheduling, particularly in highly correlated channel environments

상향링크 셀룰러 시스템에서 채널 상관 기반의 협력 사용자 스케줄링 기법

In this paper, we consider multi-user scheduling to avoid other cell interference (OCI) in the uplink of cellular systems. The base station (BS) determines a user group that can minimize the interference from other cells by exploiting the spatial correlation matrix of users from adjacent BSs. The proposed scheme is applicable to multi-input multi-output (MIMO) as well as single-input multi-output (SIMO) environments by applying an eigen-beamforming technique, enabling the use of flexible antenna structures at the transmitter. Simulation results show that the proposed multi-cell scheduling significantly increase the ergodic capacity by avoiding the OCI compared to conventional scheduling schemes, particularly in high mobility and highly correlated channel environments.Seoul R&BD Progra