다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

The objective of this paper is to give a comprehensive introduction to applied cryptography with an engineer or computer scientist in mind. The emphasis is on the knowledge needed to create practical systems which supports integrity, confidentiality, or authenticity. Topics covered includes an introduction to the concepts in cryptography, attacks against cryptographic systems, key use and handling, random bit generation, encryption modes, and message authentication codes. Recommendations on algorithms and further reading is given in the end of the paper. This paper should make the reader able to build, understand and evaluate system descriptions and designs based on the cryptographic components described in the paper.

[서평]「Applied Cryptography」

In this paper, we define and explore proofs of retrievability (PORs). A POR scheme enables an archive or back-up service (prover) to produce a concise proof that a user (verifier) can retrieve a target file F, that is, that the archive retains and reliably transmits file data sufficient for the user to recover F in its entirety.A POR may be viewed as a kind of cryptographic proof of knowledge (POK), but one specially designed to handle a large file (or bitstring) F. We explore POR protocols here in which the communication costs, number of memory accesses for the prover, and storage requirements of the user (verifier) are small parameters essentially independent of the length of F. In addition to proposing new, practical POR constructions, we explore implementation considerations and optimizations that bear on previously explored, related schemes.In a POR, unlike a POK, neither the prover nor the verifier need actually have knowledge of F. PORs give rise to a new and unusual security definition whose formulation is another contribution of our work.We view PORs as an important tool for semi-trusted online archives. Existing cryptographic techniques help users ensure the privacy and integrity of files they retrieve. It is also natural, however, for users to want to verify that archives do not delete or modify files prior to retrieval. The goal of a POR is to accomplish these checks without users having to download the files themselves. A POR can also provide quality-of-service guarantees, i.e., show that a file is retrievable within a certain time bound.

PORs: Proofs of Retrievability for Large Files

The Transmission Control Protocol.

Resource scheduling in cloud is a challenging job and the scheduling of appropriate resources to cloud workloads depends on the QoS requirements of cloud applications. In cloud environment, heterogeneity, uncertainty and dispersion of resources encounters problems of allocation of resources, which cannot be addressed with existing resource allocation policies. Researchers still face troubles to select the efficient and appropriate resource scheduling algorithm for a specific workload from the existing literature of resource scheduling algorithms. This research depicts a broad methodical literature analysis of resource management in the area of cloud in general and cloud resource scheduling in specific. In this survey, standard methodical literature analysis technique is used based on a complete collection of 110 research papers out of large collection of 1206 research papers published in 19 foremost workshops, symposiums and conferences and 11 prominent journals. The current status of resource scheduling in cloud computing is distributed into various categories. Methodical analysis of resource scheduling in cloud computing is presented, resource scheduling algorithms and management, its types and benefits with tools, resource scheduling aspects and resource distribution policies are described. The literature concerning to thirteen types of resource scheduling algorithms has also been stated. Further, eight types of resource distribution policies are described. Methodical analysis of this research work will help researchers to find the important characteristics of resource scheduling algorithms and also will help to select most suitable algorithm for scheduling a specific workload. Future research directions have also been suggested in this research work.

A Survey on Resource Scheduling in Cloud Computing: Issues and Challenges

Public-key cryptography can be claimed as the greatest and an excellent revolution in the field of cryptography. A public-key cryptosystem is used for both confidentiality and authentication. One such public-key cryptosystem is the RSA cryptosystem. In this paper, a modified and an enhanced scheme based on RSA public-key cryptosystem is developed. The proposed algorithm makes use of four large prime numbers which increases the complexity of the system as compared to traditional RSA algorithm which is based on only two large prime numbers. In the proposed Enhanced and Secured RSA Key Generation Scheme (ESRKGS), the public component n is the product of two large prime numbers but the values of Encryption (E) and Decryption (D) keys are based on the product of four large prime numbers (N) making the system highly secured. With the existing factorization techniques, it is possible only to find the primes p and q. The knowledge of n alone is not sufficient to find E and D as they are based on N. The time required for cryptanalysis of ESRKGS is higher than traditional RSA cryptosystem. Thus the system is highly secure and not easily breakable. A comparison is done between the traditional RSA scheme, a recent RSA modified scheme and our scheme to show that the proposed technique is efficient.

An Enhanced and Secured RSA Key Generation Scheme (ESRKGS)

The objective of Optimal Workflow based Scheduling (OWS) algorithm is to find a solution that meets the user-preferred Quality of Service (QoS) parameters. The work presented focuses on scheduling cloud workflows. First, the Resource discovery algorithm, indexes all the resources and this helps in locating the free resources. Second, the scheduling algorithm that takes user specified QoS parameters (execution time, reliability, monetary cost etc.) as key factor is used for scheduling workflows. Using a special metric called the QoS heuristic, the sub-task cluster is assigned to its optimal resource. Third, in case resources are not available for allocating to a task, compaction is performed. By this a significant improvement in CPU utilization is achieved.

An Optimal Workflow Based Scheduling and Resource Allocation in Cloud

Brain tumor is the cancerous disease where abnormal cells found in the brain. This can be cured if we detect the brain tumor at an early stage. In this proposed system the tumor area is marked and defined what kind of tumor present in the brain tumor MRI image. AlexNet model is used for the classification of different types of tumors as a base model along with Region Proposal Network (RPN) by Faster R-CNN algorithm. Here, the concept of transfer learning is used during training. The proposed system helps to predict the correct type of tumor with better accuracy.

Tumor Detection in the Brain using Faster R-CNN

In response to the coronavirus (COVID-19) pandemic, Government and public health authorities around the world are developing contact tracing apps as a way to trace and slow the unfold of the virus. There is major divergence among nations, however, between a "privacy-first" approach that protects citizens' information at the price of very restricted access for public health authorities and a "data-first" approach that stores massive amounts of knowledge that, whereas of immeasurable price to epidemiologists. Contact tracing apps work by gathering information from people who have tested positive for the virus and so locating and notifying individuals with whom those people are in shut contact, oftentimes by use of GPS, Bluetooth, or wireless technology. All of the user's information is employed and picked up, the study found that users' information would be created anonymous, encrypted, secured, and can be transmitted on-line and stored solely in an aggregated format. Contact tracing apps use either a centralized or a decentralized approach to work the user's information. Apps that use a centralized approach have high privacy risks. In this paper, the researcher's contributions related to the security and privacy of Contact tracing apps have been discussed and, later research gaps have been identified with proposed solutions.

/pdf/a-survey-on-security-and-privacy-issues-in-contact-tracing-2g4413g5ac.pdf

P. Varalakshmi

Papers

An Enhanced and Secured RSA Key Generation Scheme (ESRKGS)

An Optimal Workflow Based Scheduling and Resource Allocation in Cloud

Tumor Detection in the Brain using Faster R-CNN

A Survey on Security and Privacy Issues in Contact Tracing Application of Covid-19

Thwarting DDoS attacks in grid using information divergence