Papers by Ashish Vashistha
— Location-based routing algorithms eradicate some of the limitations of topology-based routing b... more — Location-based routing algorithms eradicate some of the limitations of topology-based routing by using the information of the physical location of the participating nodes; therefore they are good candidates for VANETs. One type of capable location-based routing algorithm is location-based greedy forwarding: a node forwards a packet to its one-hop neighbour that is located closer to the destination than itself. Since vehicles can move with a high speed, the vehicle’s moving direction has been regarded as a very important factor in routing decisions. As a consequence, the authentication of the supplier of traffic situation information and the authorization of entity’s to admittance this information is essential. Accordingly it’s indispensable to expand an advance security method for VANETs protocol. In this paper to proposed progress the security of location-based routing. This illumination can challenge almost each of the attacks, still those attacks which at in attendance obtainab...
Ijca Proceedings on National Seminar on Recent Advances in Wireless Networks and Communications, Apr 18, 2014
In vehicular ad hoc networks clever traffic services are efficient if they are connected with met... more In vehicular ad hoc networks clever traffic services are efficient if they are connected with method that supervise and create trust among service providers and vehicles. Consequently, the authentication of the providers of traffic condition information and the authorization of entity's to admittance this information is crucial. Consequently it's essential to extend a innovative security scheme for VANETs protocol.
International Journal of Computer Applications, 2013
This paper discuses comparatively more efficient and cost effective scheme of El Gamal Cryptosyst... more This paper discuses comparatively more efficient and cost effective scheme of El Gamal Cryptosystem by introducing the concept of using the established cryptosystems into message feedback mode. The idea behind this is, "an established cryptographic scheme can be used to initiate any communication, and further users may switch to some lightweight process so that the degree of secrecy is maintained by means of the public key cryptosystem and the performance is achieved by using some other lightweight process. Approach discussed in this paper is of using message itself as One Time Pad (OTP), because any automation can"t produce any random pad than a human being, and their messages posses same property. The length of Key used in El Gamal encryption and size of OTP determines the level of secrecy offered by the proposed system. Further a discussion is made upon the other dimensions of degree of security provided in such implementation. So as a result an applied approach is presented to design a data security mechanism for which users will use message itself as a One Time Pad and El Gamal Cryptosystem to initiate the operations and subsequent steps will involve simple XOR operations for cryptographic purpose.
Time Analysis of Chaotic Cryptosystem Using External Key with Diverse Chaotic Maps
Confluence 2013: The Next Generation Information Technology Summit (4th International Conference), 2013
In recent years, external key was introduced to chaotic cryptography and find its application in ... more In recent years, external key was introduced to chaotic cryptography and find its application in several discrete chaotic cryptosystems .The first part of this paper shows the better chaotic cryptosystem with external key. Then, we have given the classification of chaotic maps on the basis of their space dimensions. The maps functional on the chaotic cryptosystem are one space dimension maps. In this paper time analysis of the enhanced cryptosystem based on the three chaotic maps is prepared. Simulation results shows how a single chaotic cryptosystem results different Encryption/Decryption time when we made change in the type of chaotic map.
— Location-based routing algorithms eradicate some of the limitations of topology-based routing b... more — Location-based routing algorithms eradicate some of the limitations of topology-based routing by using the information of the physical location of the participating nodes; therefore they are good candidates for VANETs. One type of capable location-based routing algorithm is location-based greedy forwarding: a node forwards a packet to its one-hop neighbour that is located closer to the destination than itself. Since vehicles can move with a high speed, the vehicle’s moving direction has been regarded as a very important factor in routing decisions. As a consequence, the authentication of the supplier of traffic situation information and the authorization of entity’s to admittance this information is essential. Accordingly it’s indispensable to expand an advance security method for VANETs protocol. In this paper to proposed progress the security of location-based routing. This illumination can challenge almost each of the attacks, still those attacks which at in attendance obtainab...
The Management of Mirizzi Syndrome in the Laparoscopic Era
Surgical Laparoscopy, Endoscopy & Percutaneous Techniques, 2000
Mirizzi syndrome is a rare complication of long-standing gallstone disease resulting in obstructi... more Mirizzi syndrome is a rare complication of long-standing gallstone disease resulting in obstructive jaundice. Careful perioperative management is of utmost importance because of an increased risk of bile duct injury intraoperatively. Experience with Mirizzi syndrome over a period of 3 years, from January 1996 to December 1998, was reviewed. Twenty-seven patients were operated upon, which constituted 0.9% of 2840 patients who underwent laparoscopic cholecystectomy in the authors' department. There were 12 patients with Mirizzi type I syndrome and 15 patients with Mirizzi type II syndrome, according to McSherry classification. Six (22%) conversions were reported, all because of unclear anatomy and inherent limitations of the laparoscopic approach. For the remaining 21 (78%) patients, the procedure was completed laparoscopically. No bilioenteric anastomosis was required. A preoperative stent insertion in the common bile duct (CBD) during endoscopic retrograde cholangiopancreatography (ERCP) enabled us to achieve primary closure of CBD in every case. There was no perioperative mortality, and patients remained well for an average 2.1-year follow-up. It is highly desirable to have a preoperative diagnosis of Mirizzi syndrome, and the laparoscopic approach is not a contraindication in specialized centers. Our current management protocol to treat Mirizzi syndrome consists of a high degree of suspicion at ERCP, with stenting preoperatively and a complete stone clearance with subtotal cholecystectomy intraoperatively.
Ijca Proceedings on National Seminar on Recent Advances in Wireless Networks and Communications, Apr 18, 2014
In vehicular ad hoc networks clever traffic services are efficient if they are connected with met... more In vehicular ad hoc networks clever traffic services are efficient if they are connected with method that supervise and create trust among service providers and vehicles. Consequently, the authentication of the providers of traffic condition information and the authorization of entity's to admittance this information is crucial. Consequently it's essential to extend a innovative security scheme for VANETs protocol.
Laparoscopic Excision of a Lower Posterior Mediastinal Paraspinal Mass
Surgical Laparoscopy, Endoscopy & Percutaneous Techniques, 2002
Paravertebral and paraspinal tumors in the posterior mediastinum are predominantly neurogenic in ... more Paravertebral and paraspinal tumors in the posterior mediastinum are predominantly neurogenic in origin. The treatment comprises surgical extirpation. We report a case of a 40-year-old man with a 2-month history of pain epigastrium, radiating to the left scapula, and marked (10 kg) weight loss. Preoperative CT scan showed a paraspinal mass 8 cm in diameter at the level of the tenth thoracic vertebra. A CT scan-guided fine-needle aspiration cytologic analysis revealed the mass to be of neurogenic origin. Transabdominal laparoscopic excision of this lower posterior mediastinal neurogenic tumor was attempted and accomplished safely. The approach was through the left crural fibers, which were split to access the lower posterior mediastinum. Operating time was 122 minutes. Postoperatively, a left intercostal drain was inserted. The patient was discharged on the third postoperative day, after intercostal drain removal. Lower posterior mediastinal paraspinal tumors can be resected laparoscopically with careful preoperative investigation for tumor localization and a meticulous laparoscopic technique. A major advantage of transabdominal laparoscopic resection, as compared with open or thoracoscopic (VATS) excision, is that the patient recovers rapidly with minimal operative and anesthetic morbidity.
Journal of Laparoendoscopic & Advanced Surgical Techniques, 2000
Background and Purpose: The essential surgical steps in laparoscopic cholecystectomy remain sim- ... more Background and Purpose: The essential surgical steps in laparoscopic cholecystectomy remain sim- ilar to those of open cholecystectomy. Positive identification of the biliary anatomy, safe clipping or ligature of the cystic duct and artery, and dissection of the gallbladder from the liver bed form the basis of cholecystectomy. Subtotal cholecystectomy is a definitive and safe operation under certain adverse conditions intraoperatively for dissection of the gallbladder from the liver bed. We reviewed our experience with laparoscopic cholecystectomy over a 2-year period between June 1996 and May 1998, when 1680 operations were performed. The objective was to analyze the pathology, review surgical procedures, and trace the outcome of laparoscopic subtotal cholecystectomy. Patients and Methods: In 56 of 1680 patients, laparoscopic subtotal cholecystectomy was per- formed, which constituted 3.33% of the laparoscopic cholecystectomies performed at our institu- tion. Dense fibrosis and adhesions were present in 32 patients; 12 patients had Mirizzi syndrome, 6 patients had a sessile gallbladder, and 6 patients had a gangrenous gallbladder. The Endo-GIA 30 stapler was used in 40 patients, sequential clips were used in 9 patients, and a suture for stump clo- sure was used in 5 patients. A subhepatic drain was inserted in 50 patients. Results: Two conversions to open surgery were needed because of gangrene of the gall bladder wall and one conversion as a result of continued bleeding from the cystic artery after application of the Endo-GIA 30 stapler. The mean postoperative stay in hospital was 2.5 days. One patient had a solitary bile duct calculus extracted at endoscopie retrograde cholangiopancreatography 3 months after surgery. Three patients had biliary drainage that lasted for a week, and four patients had epi- gastric port-site infections that resolved with antibiotics, dressings and postural drainage. Conclusion: Laparoscopic subtotal cholecystectomy is safe, feasible, and effective and may help prevent conversion to open surgery in carefully selected patients with difficult cholecystectomies.
Journal of Laparoendoscopic & Advanced Surgical Techniques, 2003
Surgery has remained the mainstay for the treatment of hydatid cyst. The rapid development of lap... more Surgery has remained the mainstay for the treatment of hydatid cyst. The rapid development of laparoscopic techniques has encouraged surgeons to replicate principles of conventional hydatid surgery using a minimally invasive approach. Several reports have confirmed the feasibility of laparoscopic hepatic hydatid surgery. We report the use of a laparoscopic approach for cysts located in the liver, lung, and retroperitoneum. Fifteen patients with hydatid cysts, including one patient with a recurrent cyst, of various organs, including the liver, lung, and retroperitoneum, were operated on laparoscopically. Sixteen hydatid cysts were drained in a total of 15 patients. The mean operative time was 84 6 6 minutes (60-125 minutes). The mean duration of the hospital stay was 2.3 days (1-6 days). The mean cyst diameter was 9.2 cm (6.4-13.5 cm). No conversions to open surgery were required. One complication, a trocar-induced bowel perforation, occurred, and there was no mortality. During 3 to 44 months (mean, 27 months) of follow-up, no recurrences developed. Minimal access surgery is a safe, effective, and viable option for the management of selected patients with hydatid cysts in various locations, such as the liver, lung, and retroperitoneum.
Journal of Laparoendoscopic & Advanced Surgical Techniques, 2002
Background: Choledochal cyst is a rare congenital anomaly of the biliary tract. With increased fa... more Background: Choledochal cyst is a rare congenital anomaly of the biliary tract. With increased familiarity with the laparoscopic anatomy of the biliary tract and advances in minimally invasive techniques, surgeons have ventured further to operate on technically difficult cases such as choledochal cyst that were until recently managed by laparotomy. Patients and Methods: We present our experience with two female patients aged 14 years and 26 years with choledochal cyst (type I according to the Alonzo-Lej classification) that were successfully excised with construction of a Roux-en-Y hepaticojejunostomy entirely laparoscopically. Results: Both patients had an uneventful recovery, with no major morbidity. The first patient had a bile leak, which resolved over 5 days. Both were discharged by the 5 th postoperative day. Conclusion: Laparoscopic management of choledochal cyst is feasible although technically difficult and may be performed in specialized institutes dealing with advanced laparoscopic surgery.
Journal of Laparoendoscopic & Advanced Surgical Techniques, 2001
Background: Mature symptomatic pancreatic pseudocysts require surgical intervention for their man... more Background: Mature symptomatic pancreatic pseudocysts require surgical intervention for their management. In this era of minimal access surgery, several reports are now available of laparoscopic management of pancreatic pseudocysts. Patients and Methods: We have performed this procedure in five patients over the past 2 years. Four patients developed the pseudocyst after acute alcoholic pancreatitis and one following acute biliary pancreatitis. The diameter of the pseudocyst ranged from 8 to 12 cm. The procedure was performed using five ports. The Harmonic Scalpel was used to create two ports in the anterior stomach wall through which two balloon trocars were placed into the gastric lumen. Following balloon inflation, the trocars were used to lift up the anterior gastric wall. This created the space for the cystogastrostomy to be fashioned laparoscopically through the balloon trocar. The ball probe of the Harmonic Scalpel was used to puncture the cyst through the posterior gastric wall. The cystogastrostomy was completed by firing an Endo-GIA30 stapler across the fused posterior gastric wall and anterior wall of the cyst. Results: The mean operative time was 90 minutes (range 80-125 minutes). The mean postoperative stay was 3.0 days. One patient had intraoperative bleeding at the anastomotic site, which was easily controlled. Conclusion: Laparoscopic cystogastrostomy offers a feasible and safe therapeutic option for selected patients with large symptomatic pancreatic pseudocysts.
Journal of Laparoendoscopic & Advanced Surgical Techniques, 1999
There have now been several attempts at neck exploration using minimally invasive surgery. These ... more There have now been several attempts at neck exploration using minimally invasive surgery. These encouraging reports paved the way for the authors to attempt endoscopie neck surgery. Having the necessary technical expertise in minimally invasive surgery with an experience of more than 6000 laparoscopic procedures, they attempted endoscopie parathyroidectomy in three patients with hyperparathyroidism. Of these, two had a hyperfunctioning adenoma and one had parathyroid hyperplasia. The hyperfunctioning tissue was accurately localized using a 99Tc-thallium subtraction scan. It was possible to localize and dissect the parathyroid tissue in two of the three patients. One patient required an open hemithyroidectomy before the adenoma could be localized and excised. The total operative time averaged 113 min. The working space was found to be adequate provided good hemostasis was maintained. The magnification proved excellent in identifying and defining important neck structures. Sufficient mobilization of the lateral thyroid lobe for access to the tracheoesophageal groove was found to be technically very difficult. No subcutaneous emphysema was observed beyond the neck region, and none lasted beyond 24 h. Cosmesis was acceptable to both the patient and the surgeon.
AODV with Route Backup List Routing Algorithm for Mobile Ad Hoc Networks
A mobile ad hoc network is a multi hop wireless network created by a group of mobile nodes that h... more A mobile ad hoc network is a multi hop wireless network created by a group of mobile nodes that have wireless potential Connections in MANET (Mobile Ad hoc Networks) are recognized and withdraw dynamically as the network is dynamic. The mobile nodes in the network can connect and go away the network anytime. Communication of information becomes neither challenging in such networks where the position of a node is neither fixed nor the link joining the two nodes permanent. Efficient protocols are required for uninterrupted transmission of data in the network. Research in the field of designing a better algorithm is an upcoming area, the probable result of which is an efficient algorithm which can facilitate better performance. This work offer improved AODV (Ad hoc On demand Distance Vector) routing algorithm named as AODVRBL which helps in fast rebuilding of the broken links from source to target. Algorithm maintains a backup list at the source node containing all the possible routes ...
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Papers by Ashish Vashistha