Data Sciences Challenges
Explore data science challenges on Ewance to build skills employers expect from analysts and ML engineers. Work through challenges on data cleaning, exploratory analysis, modeling, and storytelling with data.
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- AnalysisIntermediateNew
Diagnose a Memory-Hierarchy Bottleneck in a Trading-System Hot Path
Receive the normalizer source (around 4,000 lines of C++17), a replay harness that feeds 30 minutes of recorded market data, and host-machine specifications (Intel Xeon Gold 634…
- Memory Hierarchy
- Performance Profiling
- Perf
Computer Systems and Organization - CodeIntermediateNew
Apply Software Transactional Memory to a Real-Time Auction Book
Implement two variants of the same auction-book API (best-bid/best-ask lookup, place-order, cancel-order, match-orders): (1) baseline with java.util.concurrent locks + a SkipLis…
- Transactional Memory
- Concurrent Data Structures
- Haskell
Advanced Concurrency and Parallel Computing - DesignIntermediateNew
Design Multi-Tenant Network Policies with Calico Tier Enforcement
Receive the cluster topology (120 customer namespaces + 4 platform namespaces), the application traffic patterns (frontend talks to backend talks to its tenant's database), and …
- Kubernetes
- Network Policy
- Calico
Container Orchestration with Kubernetes - CodeIntermediateNew
Migrate Stateful Workloads to StatefulSets with Storage Class Tuning
Receive the current Redis Sentinel topology (3 nodes, ~120GB data), the EBS gp3 baseline performance requirements (3,000 IOPS, 125 MB/s), and the cluster (EKS 1.29 with the EBS …
- Kubernetes
- Statefulsets
- Storage Classes
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Why Ewance
- AnalysisIntermediateNew
Mine Basket History to Justify Grocery Shelf-Adjacency Changes
Work only from the materials provided. Use the basket transactions extract to mine frequent itemsets with FP-growth, tuning the minimum support level separately for the food, ho…
- Frequent Itemset Mining
- Fp Growth
- Spark
Open coursework - CodeIntermediateNew
Build a Hybrid Recommendation System for an Indie Streaming Catalog
Use the provided 6-month anonymized event log (around 320M play events, 1.4M unique users in the held-out cohort), audio embeddings (256-d), and track metadata. Implement (1) an…
- Recommendation Systems
- Collaborative Filtering
- Content Based Recommendation
Data Mining and Information Retrieval - CodeIntermediateNew
Design a Lock-Free Concurrent Queue for an Event Bus
Implement an MPSC (multi-producer single-consumer) ring-buffer queue in Go using atomic operations only — no mutexes. Prove correctness with the Go race detector across 8 produc…
- Concurrent Data Structures
- Lock Free Programming
- Go
Data Structures - CodeIntermediateNew
Index a Reference Genome with a Suffix Array in Rust
Using the reference-genome FASTA in the provided materials, build an in-memory suffix array (DC3 or SA-IS construction) over the 4-letter DNA alphabet in Rust, then implement co…
- Suffix Arrays
- String Algorithms
- Rust
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Strategy Analyst
Frame the business question, model the options, build the recommendation. From market sizing to competitive analysis, this role is where strategy consulting meets in-house decision-making.
- DesignIntermediateNew
Design an Interactive Subway On-Time Performance Visualization
Using the provided arrival-performance sample dataset, design a small-multiples layout — one compact panel per subway line — that uses a horizon-chart encoding to show on-time p…
- D3
- Webgl
- Interactive Visualization
Open coursework - ResearchIntermediateNew
Recommend a Color Scale for a Flood-Risk Map With Evidence
Working only from the provided materials, reach and defend a single recommendation. Read the decision file (decision-file) to understand the actors, the prior complaint, and the…
- Perceptual Study
- Color Scales
- Experimental Design
Open coursework - DesignIntermediateNew
Author a Scrollytelling Story on a Three-Week Ad-Fraud Anomaly
Using the internal investigation report (provided) and the anomaly dataset (provided), design a seven-section scrollytelling narrative and build it as a static web page. Structu…
- Narrative Visualization
- Scrollytelling
- Svelte
Open coursework - CodeIntermediateNew
Build a WCAG 2.2 AA Accessible Chart Component Library
Build a React and TypeScript component library that exports four chart components (bar, line, scatter, heatmap), each rendering the figures in the provided sample analytics data…
- Accessibility
- Wcag 2
- React
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- DesignIntermediateNew
Resolve the Quota Double-Spend: Design Meterly's Order-Provisioning Schema
Working only from the materials provided, reach and defend a database design. Read the de-identified incident record (incident-file) and the business-rules brief (requirements-b…
- Transactions
- Acid
- Isolation Levels
Open coursework - CodeIntermediateNew
Tame Lock Contention on a Shared Property-Manager CRM Database
Working only from the four provided materials, produce a fix-and-prove package. Start with the recorded lock snapshots (lock_snapshots) and the environment case file (db_environ…
- Concurrency Control
- Lock Contention
- Postgresql
Open coursework - DesignIntermediateNew
Design a Zero-Downtime Multi-Region PostgreSQL Migration for an EdTech Platform
Using the infrastructure inventory (infra-inventory), the database schema sample (schema-subset), the workload metrics (workload-metrics), and the service-level brief (sla-brief…
- Blue Green Deployment
- Logical Replication
- Postgresql
Open coursework - DesignIntermediateNew
Rescue a 3x3 Convolution Accelerator on Zynq UltraScale+
Working only from the materials provided, reach and defend an engineering judgment, then deliver the working accelerator that proves it. Read the engineering case file ('vision-…
- Systemverilog
- Fpga
- Axi Stream
Open coursework - AnalysisIntermediateNew
Tune Database Consistency for a Ride-Hailing Match Engine
Working only from the materials provided, analyse why the matching glitch appears under load and argue for a consistency policy per query class. Start from the cluster topology …
- Consistency Models
- Cassandra
- Distributed Tracing
Open coursework - DesignIntermediateNew
Migrate a 6TB Social-Commerce Database to a Sharded Topology
Using the supplied schema specification and the seven-day anonymized query-workload export, decide the correct shard key for each table and justify it from observed access patte…
- Database Sharding
- Postgresql
- Vitess
Open coursework - DesignIntermediateNew
Design a Region-Routed Storage Layer for a Nordic EdTech
Working only from the materials in this file, produce a recommendation for how Lärnova should store student assignments so each country's data stays in its home region. Start by…
- Geo Distribution
- Data Residency
- Cockroachdb
Open coursework - CodeIntermediateNew
Design an Anti-Corruption Layer for a Legacy Hospital EHR
Map the legacy EHR's HL7 v2 message schema (ADT, ORM, ORU segments) to the new platform's domain (Patient, Encounter, Order, Result). Identify the 6-10 anti-patterns in the lega…
- Anti Corruption Layer
- Hl7 Integration
- Domain Modeling
Domain-Driven Design - CodeIntermediateNew
Apply Hexagonal Architecture to a Payments Microservice
Design the settlement domain in pure Kotlin (no Spring imports, no framework annotations). Define ports for: payment-network adapter (one inbound per network — SEPA, Faster Paym…
- Hexagonal Architecture
- Ports And Adapters
- Kotlin Programming
Domain-Driven Design - DesignIntermediateNew
Replace Nightly Batch Loads with Near-Real-Time Reporting at a Pump Manufacturer
Using the system inventory in the provided case-file, classify all nine source systems by the most appropriate way to capture their changes: log-based change data capture where …
- Change Data Capture
- Kafka
- Debezium
Open coursework - AnalysisIntermediateNew
Audit and Govern a Frankfurt Bank's Sprawling API Estate
Working only from the materials provided, examine the API estate and reach a defensible governance judgment. Read the situation record (estate-situation-file) to understand how …
- API Governance
- Openapi Spec
- Dora Compliance
Open coursework - CodeIntermediateNew
Bridge a Healthcare Messaging System from RabbitMQ to Kafka
Working from the provided RabbitMQ topology specification and the 30-day message-volume dataset, map each of the 24 queues to a Kafka topic and choose a sound partition key for …
- Kafka
- Rabbitmq
- Message Broker Migration
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