scholarly journals Comparison on Search Failure between Hash Tables and a Functional Bloom Filter

2020 ◽  
Vol 10 (15) ◽  
pp. 5218 ◽  
Author(s):  
Hayoung Byun ◽  
Hyesook Lim
Keyword(s):  
Failure Rate ◽  
Data Structures ◽  
Hash Table ◽  
Bloom Filter ◽  
Load Factor ◽  
Failure Rates ◽  
Hash Tables ◽  
Collision Problem ◽  
Simulation Results ◽  
Return Value

Hash-based data structures have been widely used in many applications. An intrinsic problem of hashing is collision, in which two or more elements are hashed to the same value. If a hash table is heavily loaded, more collisions would occur. Elements that could not be stored in a hash table because of the collision cause search failures. Many variant structures have been studied to reduce the number of collisions, but none of the structures completely solves the collision problem. In this paper, we claim that a functional Bloom filter (FBF) provides a lower search failure rate than hash tables, when a hash table is heavily loaded. In other words, a hash table can be replaced with an FBF because the FBF is more effective than hash tables in the search failure rate in storing a large amount of data to a limited size of memory. While hash tables require to store each input key in addition to its return value, a functional Bloom filter stores return values without input keys, because different index combinations according to each input key can be used to identify the input key. In search failure rates, we theoretically compare the FBF with hash-based data structures, such as multi-hash table, cuckoo hash table, and d-left hash table. We also provide simulation results to prove the validity of our theoretical results. The simulation results show that the search failure rates of hash tables are larger than that of the functional Bloom filter when the load factor is larger than 0.6.

FMPC: A Fast Multi-Dimensional Packet Classification Algorithm

2014 ◽  
Vol 644-650 ◽  
pp. 3365-3370
Author(s):  
Zhen Hong Guo ◽  
Lin Li ◽  
Qing Wang ◽  
Meng Lin ◽  
Rui Pan
Keyword(s):  
Rapid Development ◽  
Hash Table ◽  
Bloom Filter ◽  
Packet Classification ◽  
Binary Search ◽  
Bloom Filters ◽  
Algorithm Analysis ◽  
Hash Tables ◽  
Worst Case ◽  
Embedded Sram

With the rapid development of the Internet, the number of firewall rules is increasing. The enormous quantity of rules challenges the performance of the packet classification that has already become a bottleneck in firewalls. This dissertation proposes a rapid and multi-dimensional algorithm for packet classification based on BSOL(Binary Search On Leaves), which is named FMPC(FastMulti-dimensional Packet Classification). Different from BSOL, FMPC cuts all dimensions at the same time to decompose rule spaces and stores leaf spaces into hash tables; FMPC constructs a Bloom Filter for every hash table and stores them into embedded SRAM. When classifying a packet, FMPC performs parallel queries on Bloom Filters and determines how to visit hash tables according to the results. Algorithm analysis and the result of simulations show: the average number of hash-table lookups of FMPC is 1 when classifying a packet, which is much smaller than that of BSOL; inthe worst case, the number of hash-table lookups of FMPCisO(logwmax+1⁡), which is also smaller than that of BSOL in multi-dimensional environment, where wmax is the length, in bits, of the dimension whose length is the longest..

scholarly journals HashGraph—Scalable Hash Tables Using a Sparse Graph Data Structure

2021 ◽  
Vol 8 (2) ◽  
pp. 1-17
Author(s):  
Oded Green
Keyword(s):  
Data Structures ◽  
Recent Progress ◽  
State Of The Art ◽  
Hash Table ◽  
Sparse Graph ◽  
Dynamic Graph ◽  
Hash Tables ◽  
Graph Representations ◽  
Graph Data ◽  
Open Addressing

In this article, we introduce HashGraph, a new scalable approach for building hash tables that uses concepts taken from sparse graph representations—hence, the name HashGraph. HashGraph introduces a new way to deal with hash-collisions that does not use “open-addressing” or “separate-chaining,” yet it has the benefits of both these approaches. HashGraph currently works for static inputs. Recent progress with dynamic graph data structures suggests that HashGraph might be extendable to dynamic inputs as well. We show that HashGraph can deal with a large number of hash values per entry without loss of performance. Last, we show a new querying algorithm for value lookups. We experimentally compare HashGraph to several state-of-the-art implementations and find that it outperforms them on average 2× when the inputs are unique and by as much as 40× when the input contains duplicates. The implementation of HashGraph in this article is for NVIDIA GPUs. HashGraph can build a hash table at a rate of 2.5 billion keys per second on a NVIDIA GV100 GPU and can query at nearly the same rate.

Scaling Dynamic Hash Tables on Real Persistent Memory

2021 ◽  
Vol 50 (1) ◽  
pp. 87-94
Author(s):  
Baotong Lu ◽  
Xiangpeng Hao ◽  
Tianzheng Wang ◽  
Eric Lo
Keyword(s):  
Hash Table ◽  
High Load ◽  
Low Latency ◽  
Load Factor ◽  
Hash Tables ◽  
Persistent Memory ◽  
Memory Modules

Byte-addressable persistent memory (PM) brings hash tables the potential of low latency, cheap persistence and instant recovery. The recent advent of Intel Optane DC Persistent Memory Modules (DCPMM) further accelerates this trend. Many new hash table designs have been proposed, but most of them were based on emulation and perform sub-optimally on real PM. They were also piecewise and partial solutions that side-stepped many important properties, in particular good scalability, high load factor and instant recovery.

Electromigration and Electrochemical Reaction Mixed Failure Mechanism in Gold Interconnection System

1999 ◽  
Author(s):  
Hide Murayama ◽  
Makoto Yamazaki ◽  
Shigeru Nakajima
Keyword(s):  
Failure Mechanism ◽  
Failure Rate ◽  
Electrochemical Reaction ◽  
Dielectric Films ◽  
Failure Rates ◽  
Interlayer Dielectric ◽  
Bipolar Devices ◽  
Gold Metallization

Abstract Power bipolar devices with gold metallization experience high failure rates. The failures are characterized as shorts, detected during LSI testing at burn-in. Many of these shorted locations are the same for the failed devices. From a statistical lot analysis, it is found that the short failure rate is higher for devices with thinner interlayer dielectric films. Based upon these results, a new electromigration and electrochemical reaction mixed failure mechanism is proposed for the failure.

Outcomes of Inside-out Meniscal Repair in the Setting of Multiligament Reconstruction in the Knee

2017 ◽  
Vol 45 (9) ◽  
pp. 2098-2104 ◽  
Author(s):  
Jorge Chahla ◽  
Chase S. Dean ◽  
Lauren M. Matheny ◽  
Justin J. Mitchell ◽  
Mark E. Cinque ◽  
...  
Keyword(s):  
Failure Rate ◽  
Meniscal Repair ◽  
Postoperative Outcome ◽  
Control Group ◽  
Failure Rates ◽  
Significant Difference ◽  
Outcome Scores ◽  
Inside Out ◽  
Repair Group

Background: Limited evidence exists for meniscal repair outcomes in a multiligament reconstruction setting. Purpose/Hypothesis: The purpose of this study was to assess outcomes and failure rates of meniscal repair in patients who underwent multiligament reconstruction compared with patients who underwent multiligament reconstruction but lacked meniscal tears. The authors hypothesized that the outcomes of meniscal repair associated with concomitant multiligament reconstruction would significantly improve from preoperatively to postoperatively at a minimum of 2 years after the index surgery. Secondarily, they hypothesized that this cohort would demonstrate similar outcomes and failure rates compared with the cohort that did not have meniscal lesions at the time of multiligament reconstruction. Study Design: Cohort study; Level of evidence, 3. Methods: Inclusion criteria for the study included radiographically confirmed skeletally mature patients of at least 16 years of age who underwent multiligamentous reconstruction of the knee without previous ipsilateral osteotomy, intra-articular infections, or intra-articular fractures. Patients were included in the experimental group if they underwent inside-out meniscal suture repair with concurrent multiligament reconstruction. Those included in the control group (multiligament reconstruction without a meniscal tear) underwent multiligament reconstruction but did not undergo any type of meniscal surgery. Lysholm, Western Ontario and McMaster Universities Osteoarthritis Index, Short Form–12 physical component summary and mental component summary, Tegner activity scale, and patient satisfaction scores were recorded preoperatively and postoperatively. The failure of meniscal repair was defined as a retear of the meniscus that was confirmed arthroscopically. Results: There were 43 patients (16 female, 27 male) in the meniscal repair group and 62 patients (25 female, 37 male) in the control group. Follow-up was obtained in 93% of patients with a mean of 3.0 years (range, 2.0-4.7 years). There was a significant improvement between all preoperative and postoperative outcome scores ( P < .05) for both groups. The meniscal repair group had significantly lower preoperative Lysholm and Tegner scores ( P = .009 and P = .02, respectively). There were no significant differences between any other outcome scores preoperatively. The failure rate of the meniscal repair group was 2.7%, consisting of 1 symptomatic meniscal retear. There was no significant difference in any postoperative outcome score at a minimum 2-year follow-up between the 2 groups. Conclusion: Good to excellent patient-reported outcomes were reported for both groups with no significant differences in outcomes between the cohorts. Additionally, the failure rate for inside-out meniscal repair with concomitant multiligament reconstruction was low, regardless of meniscus laterality and tear characteristics. The use of multiple vertical mattress sutures and the biological augmentation resulting from intra-articular cruciate ligament reconstruction tunnel reaming may be partially responsible for the stability of the meniscal repair construct and thereby contribute to the overall improved outcomes and the low failure rate of meniscal repair, despite lower preoperative Lysholm and Tegner scores in the meniscal repair group.

scholarly journals Clinical Evaluation of Bracket Bonding Using Two Different Polymerization Sources

2008 ◽  
Vol 78 (5) ◽  
pp. 922-925 ◽  
Author(s):  
Nikolaos S. Koupis ◽  
Theodore Eliades ◽  
Athanasios E. Athanasiou
Keyword(s):  
Failure Rate ◽  
Orthodontic Treatment ◽  
Light Emitting Diode ◽  
Rank Test ◽  
Dental Arch ◽  
Halogen Lamp ◽  
Failure Rates ◽  
Bond Failure ◽  
Significant Difference ◽  
The Right

Abstract Objective: To comparatively assess clinical failure rate of brackets cured with two different photopolymerization sources after nine months of orthodontic treatment. Materials and Methods: The sample of this study comprised 30 patients who received comprehensive orthodontic treatment by means of fixed appliances. Using the same adhesive, 600 stainless steel brackets were directly bonded and light cured for 10 seconds with the light-emitting diode (LED) lamp or for 20 seconds with the conventional halogen lamp. A split-mouth design randomly alternated from patient to patient was applied. Failure rates were recorded for nine months and analyzed with Pearson χ2 test, and log-rank test at α = .05 level of significance. Results: The overall failure rate recorded with the halogen unit (3.33%) was not significantly different from the failure rate for the LED lamp (5.00%). Significantly more failures were found in boys compared with girls, in the mandibular dental arch compared with the maxillary arch, and in posterior segments compared with anterior segments. However, no significant difference was found between the right and left segments. Conclusion: Both light-curing units showed sufficiently low bond failure rates. LED curing units are an advantageous alternative to conventional halogen sources in orthodontics because they enable a reduced chair-time bonding procedure without significantly affecting bond failure rate.

Comparison of Early Implant Failure Rates Between Subjects With and Without Orthodontic Treatment Before Dental Implantation

2019 ◽  
Vol 45 (1) ◽  
pp. 29-34
Author(s):  
Li-ching Chang ◽  
I-ming Tsai
Keyword(s):  
Treatment Group ◽  
Failure Rate ◽  
Orthodontic Treatment ◽  
Implant Failure ◽  
Control Group ◽  
Failure Rates ◽  
Implant Surgery ◽  
Dental Implantation ◽  
And Control

The present study compared early dental implant failure rates between patients with and without orthodontic treatment before dental implantation. The data of adults who had undergone dental implantation between January 2007 and December 2016 were analyzed retrospectively. A total of 124 subjects with 255 implants were divided into a treatment group (46 subjects, 85 teeth) consisting of patients who had undergone implant surgery after orthodontic treatment and a control group of patients who had not undergone preimplant orthodontic treatment. Implants that failed before permanent crown fabrication were defined as failures. No significant differences in gender or age were found between the treatment group and controls. No significant differences were found in implant failure rates in either jaw between the treatment and control groups. However, the failure rate was still higher in the treatment group (14.81%) than in the control group (3.28%) for the maxilla. Results of this study demonstrate an increased implant failure rate only in the maxilla of patients who underwent orthodontic treatment before dental implantation, especially implant surgery combined with a sinus lift procedure. Further study with a larger sample size and longer follow-up period is necessary to confirm results of the present study and identify other confounding factors.

scholarly journals Varicocele surgery or embolization: Which is better?

2013 ◽  
Vol 6 (4) ◽  
pp. 266 ◽  
Author(s):  
Darby Cassidy ◽  
Keith Jarvi ◽  
Ethan Grober ◽  
Kirk Lo
Keyword(s):  
Failure Rate ◽  
Attractive Alternative ◽  
Published Data ◽  
Technical Failure ◽  
Failure Rates ◽  
Male Factor Infertility ◽  
Male Factor ◽  
Gonadal Vein ◽  
Microsurgical Approach ◽  
The Right

Introduction: Varicocele remains the most commonly identifiedcorrectable cause of male factor infertility. Surgical correction isthe most commonly performed technique to treat varicoceles with a technical failure rate of less than 5%. An attractive alternative to surgery is the selective catheterization and embolization of the gonadal vein. This data are limited by small series.Methods: We reviewed a total of 158 patients. These patientsunderwent embolization for clinical varicoceles and male factorinfertility between 2004 and 2008. Of these, 56% underwentattempted bilateral embolization, 43% unilateral left-sided embolization and 1.3% unilateral right-sided embolization.Results: Of these patients who underwent attempted bilateralembolization, 19.3% did not experience a successful obliterationof the right gonadal vein and 2.3% (2/88) experienced a failure rate in the embolization of the left gonadal vein. Of the 2 attempts at unilateral right-sided embolization, there were no failures. Of the 68 unilateral left-sided embolization attempts, there was a 4.4% failure rate. Of all of the right-sided embolization attempts, 18.9% failed, while 3.2% of the left-sided attempts failed.Conclusion: This review represents the largest contemporary series of varicocele embolization outcomes currently in the literature. Our 19.3% technical failure rate for bilateral varicocele embolization is higher than the current published rate of 13% and is largely related to failure to successfully occlude the right gonadal vein. This supports our belief that bilateral varicoceles are best managed with a primary microsurgical approach, where technical failure rates are expected to be less than 5% based on published data. Men withunilateral left-sided varicoceles should be offered both options as they have similar failure rates, but with embolization offering some clear advantages to the patient.

Risk Factors for Failure of Direct Restorations in General Dental Practices

2020 ◽  
Vol 99 (9) ◽  
pp. 1039-1046 ◽  
Author(s):  
R.J. Wierichs ◽  
E.J. Kramer ◽  
H. Meyer-Lueckel
Keyword(s):  
Failure Rate ◽  
Treatment Decision ◽  
Class I ◽  
Failure Rates ◽  
Restorative Material ◽  
Cox Proportional Hazard ◽  
Cox Proportional Hazard Models ◽  
Dental Practices ◽  
Relevant Factors

The aim of this retrospective noninterventional multicenter practice-based study was to analyze factors influencing the survival of direct restorations. Records from patients who visited 5 private practices regularly were searched for the presence of direct restorations. Data were recorded from 7,858 patients with 27,407 direct restorations being detected at least 6 mo before the last recall visit. Multilevel Cox proportional hazard models were used to evaluate the association between clinical factors and time until failure. Within 228 mo, 5,493 failures could be observed. Median survival time was 207 mo. The annual failure rates were 3.8%, 4.0%, 4.6%, 4.9%, and 3.9% for class I, II, III, IV, and V restorations, respectively. Class II and IV restorations showed a 1.1-times (95% CI, 1.0 to 1.2) and 1.2-times (95% CI, 1.1 to 1.2) higher failure rate than class I restorations ( P ≤ 0.029). Patients aged <20 y and >60 y showed up to a 1.4-times higher failure rate than patients aged 20 to 60 y ( P ≤ 0.015). Restorations that underwent check-up twice a year or more showed a significantly higher failure rate than those that did so less than twice a year ( P < 0.001). Furthermore, the dentists significantly influenced time until failure ( P < 0.001). Regarding the restorative material, composites showed up to a 2.1-times longer time until failure than GIC ( P ≤ 0.020). Moderate failure rates were observed for direct restorations in the private practice setting after up to 18.5 y. Within the limitations of the present study, several factors on the levels of practice (i.e., dentist), patient (i.e., age), and tooth (i.e., restorative material, restored surfaces according to the classification of Black) were significant predictors for the failure rate. Therefore, treatment decision should take into account most relevant factors (German Clinical Trials Register DRKS00015228).

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