بنية المترجم ثلاثية المراحل

The recovery block scheme is a software fault-tolerance technique based on design diversity and backward error recovery. It structures a program as a series of blocks, each with a primary module, an acceptance test, and one or more alternate modules. If the primary module's output fails the acceptance test, the system state is restored, and an alternate module is executed.

Verification and validation (V&V) are distinct processes. Verification ensures a product meets its specified requirements ("Are you building it right?"). Validation ensures the product meets the user's actual needs and intended use ("Are you building the right thing?"). They are complementary activities within quality management, often performed sequentially or in parallel to ensure both correctness and usefulness.

The repeatability limit, [latex]r[/latex], is a critical value derived from the repeatability standard deviation ([latex]s_r[/latex]). It represents the maximum expected absolute difference between two single test results, obtained under repeatability conditions, with a 95% probability. It is commonly calculated as [latex]r = 2.8 \times s_r[/latex]. If the difference exceeds [latex]r[/latex], the results are considered suspect.

BFT (اختصار لـ Byzantine Fault Tolerance) هي خاصية في النظام تسمح له بمواصلة العمل بشكل صحيح والتوصل إلى توافق في الآراء حتى في حال تعطل بعض مكوناته بطرق عشوائية وغير متوقعة، بما في ذلك السلوكيات الخبيثة (الأعطال البيزنطية). وهذا ضمان أقوى بكثير من مجرد تحمل أعطال بسيطة. ويتطلب ذلك حدًا أدنى من 3f+1 من المكونات الإجمالية لتحمل f من المكونات المعيبة والخبيثة.

RAID (acronym of Redundant Array of Independent Disks) is a data storage virtualization technology that combines multiple physical disk drives into one or more logical units for data redundancy, performance improvement, or both. Different RAID levels provide varying balances of reliability, availability, performance, and capacity. For example, RAID 1 mirrors data across two disks, while RAID 5 stripes data and parity across at least three disks.

Rate-Monotonic Scheduling (RMS) is a static-priority scheduling algorithm for periodic tasks in a real-time system. It assigns priorities based on task frequency: the shorter a task's period (the higher its rate), the higher its priority. RMS is an optimal static-priority algorithm, meaning if any static-priority algorithm can schedule a task set, RMS can too. Schedulability can be checked using a utilization-based test.

طريقة الحجم المحدود (FVM) هي تقنية عددية سائدة في ديناميكيات الموائع الحسابية لحل المعادلات التفاضلية الجزئية. تُقسّم هذه الطريقة المجال إلى شبكة من أحجام التحكم، وتُطبّق المعادلات الحاكمة بصيغتها التكاملية على كل حجم. بتحويل تكاملات الحجم إلى تكاملات السطح باستخدام نظرية التباعد، تُركّز هذه الطريقة على حساب تدفق الخصائص المحفوظة عبر أسطح الخلايا.

Formal verification is the use of mathematical methods to prove or disprove the correctness of a system's design with respect to a formal specification. Unlike testing, which can only show the presence of bugs for specific inputs, formal verification can prove their absence for all possible inputs. It involves creating a formal model of the system and using techniques like model checking or theorem proving.

A statistical measure of a process's ability to produce output within customer-defined specification limits. Unlike control charts, which track stability, Cpk quantifies capability. It measures how centered the process is between the specification limits and accounts for process variation. A higher Cpk value indicates a more capable process. The formula is [latex]C_{pk} = \min\left[\frac{USL - \mu}{3\sigma}, \frac{\mu - LSL}{3\sigma}\right][/latex].

النموذج الحلزوني هو نموذج لعملية تطوير برمجيات قائم على المخاطر، يجمع بين عناصر كلٍّ من النمذجة الأولية ونموذج الشلال. وهو نوع من التطوير التكراري، حيث يمر المشروع بأربع مراحل في كل تكرار (الحلزوني): تحديد الأهداف، وتحديد المخاطر ومعالجتها، والتطوير والاختبار، والتخطيط للتكرار التالي. ويركز هذا النموذج على التحليل المستمر للمخاطر.

Signal detection is the process of identifying potential causal relationships between a drug and an adverse event from large datasets, typically spontaneous reporting systems. It uses statistical methods, known as disproportionality analysis, to find drug-event combinations reported more frequently than expected. A common measure is the Reporting Odds Ratio (ROR), a value greater than one suggesting a potential signal that requires further investigation.