Emergency Power System

Posted on by lechuck park

This image shows a diagram of an Emergency Power System and the characteristics of each component.

Overall System Structure

At the top, the power grid is connected to servers/data centers, and three backup power options are presented in case of power supply interruption.

Three Backup Power Options

1. Generator

  • Long-term operation: Unlimited operation as long as fuel is available
  • Operation method: Engine rotation → Power generation
  • Type: Diesel engine generator
  • Disadvantages:
    • Start-up delay during instantaneous power outages
    • Start-up delay, noise, exhaust emissions
    • Periodic testing required
    • Requires integration with ATS (Automatic Transfer Switch)

2. Dynamic UPS

  • Features:
    • Uninterrupted/Long-term operation (until diesel engine starts)
    • Flywheel kinetic energy storage
    • Combined generator and diesel engine
  • Advantages: Seamless power supply without STS (Static Transfer Switch)
  • Disadvantages: High initial cost, large footprint, noise

DR (Diesel Rotary) UPS: A special form of Dynamic UPS that provides uninterrupted power through flywheel energy storage technology.

3. Static UPS

  • Operation time: Instantaneous/Short-term (typically 5-15 minutes)
  • Power quality: Clean power supply
  • Configuration: Battery(DC) → Inverter(AC) → Rectifier
  • Features:
    • Millisecond-level instant transfer
    • Battery life 3-5 years, replacement costs, heat generation issues

Key Characteristics Summary

Generators can operate long-term with fuel supply but have start-up delays, while Static UPS provides immediate power but only for short durations. Dynamic UPS (including DR UPS) is a hybrid solution that provides uninterrupted power through flywheel technology while enabling long-term operation when combined with diesel engines. In actual operations, it’s common to use these systems in combination, considering the advantages and disadvantages of each system.

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Memory Bound

Posted on by lechuck park

This diagram illustrates the Memory Bound phenomenon in computer systems.

What is Memory Bound?

Memory bound refers to a situation where the overall processing speed of a computer is limited not by the computational power of the CPU, but by the rate at which data can be read from memory.

Main Causes:

  1. Large-scale Data Processing: Vast data volumes cause delays when loading data from storage devices (SSD/HDD) to DRAM
  2. Matrix Operations: Large matrices create delays in fetching data between cache, DRAM, and HBM (High Bandwidth Memory)
  3. Data Copying/Moving: Data transfer waiting times on the memory bus even within DRAM
  4. Cache Misses: When required data isn’t found in L1-L3 caches, causing slow main memory access to DRAM

Result

The Processing Elements (PEs) on the right have high computational capabilities, but the overall system performance is constrained by the slower speed of data retrieval from memory.

Summary:

Memory bound occurs when system performance is limited by memory access speed rather than computational power. This bottleneck commonly arises from large data transfers, cache misses, and memory bandwidth constraints. It represents a critical challenge in modern computing, particularly affecting GPU computing and AI/ML workloads where processing units often wait for data rather than performing calculations.

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Multi-DCs Operation with a LLM (2)

Posted on by lechuck park

This diagram illustrates a Multi-Data Center Operation with LLM architecture system configuration.

Overall Architecture Components

Left Side – Event Sources:

  • Various systems supporting different event protocols (Log, Syslog, Trap, etc.) generating events

Middle – 3-Stage Processing Pipeline:

  1. Collector – Light Blue
    • Composed of Local Integrator and Integration Deliver
    • Collects and performs initial processing of all event messages
  2. Integrator – Dark Blue
    • Stores/manages event messages in databases and log files
    • Handles data integration and normalization
  3. Analyst – Purple
    • Utilizes LLM and AI for event analysis
    • Generates event/periodic or immediate analysis messages

Core Efficiency of LLM Operations Integration (Bottom 4 Features)

  • Already Installed: Leverages pre-analyzed logical results from existing alert/event systems, enabling immediate deployment without additional infrastructure
  • Highly Reliable: Alert messages are highly deterministic data that significantly reduce LLM error possibilities and ensure stable analysis results
  • Easy Integration: Uses pre-structured alert messages, allowing simple integration with various systems without complex data preprocessing
  • Nice LLM: Operates reliably based on verified alert data and provides an optimal strategy for rapidly applying advanced LLM technology

Summary

This architecture enables rapid deployment of advanced LLM technology by leveraging existing alert infrastructure as high-quality, deterministic input data. The approach minimizes AI-related risks while maximizing operational intelligence, offering immediate deployment with proven reliability.

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Power Circuit Breaker

Posted on by lechuck park

This image presents a Power Circuit Breaker classification diagram showing the types and characteristics of electrical circuit breakers used in power systems.

System Overview

Power Flow: The diagram illustrates the electrical power path from power plant → transmission lines → circuit breakers → distribution panels.

Circuit Breaker Classification

The breakers are categorized by voltage levels and arc extinguishing methods:

Voltage Classifications

  • Very High Voltage: 66~800kV
  • High Voltage: 3.3~38kV
  • Using Voltage: 380~690V, 110~600V, 110~440V

Breaker Types and Arc Extinguishing Methods

  1. GIS/GCB (Gas Insulated Switchgear/Gas Circuit Breaker)
    • 66~800kV
    • Uses SF6 gas with high vacuum technology
  2. VCB (Vacuum Circuit Breaker)
    • 3.3~38kV
    • Vacuum arc extinguishing method
  3. ACB (Air Circuit Breaker)
    • 380~690V
    • Air + arc chute method
  4. MCCB (Molded Case Circuit Breaker)
    • 110~600V
    • Air + arc chute method
  5. ELCB (Earth Leakage Circuit Breaker)
    • 110~440V
    • Ground fault protection, no arc extinguishing

Key Safety Message

The diagram emphasizes “The bigger (Arc) the more dangerous” – highlighting that higher voltages require more sophisticated and safer arc extinguishing technologies.

Summary: This technical diagram systematically categorizes power circuit breakers from ultra-high voltage (800kV) to low voltage (110V) applications, demonstrating how arc extinguishing complexity increases with voltage levels. The chart serves as an educational reference showing that higher voltage systems require more advanced safety mechanisms like SF6 gas insulation, while lower voltage applications can use simpler air-based arc interruption methods.

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Why/When Optimization ??

Posted on by lechuck park

Analysis of Optimization Strategy Framework

Upper Graph: Stable Requirements Environment

  • Characteristics: Predictable requirements with minimal fluctuation
  • 100% Optimization Results:
    • “Very Difficult” (high implementation cost)
    • “No Efficiency” (poor ROI)
  • Conclusion: Over-optimization is unnecessary in stable environments

Lower Graph: Volatile Requirements Environment

  • Characteristics: Frequent requirement changes with high uncertainty
  • Optimization Level Analysis:
    • Peak Support (Blue): Reactive approach handling only maximum loads
    • 60-80% Optimization (Green): “Easy & High Efficiency” ⭐
    • 100% Optimization (Red): “Very Difficult” + “Still No Efficiency”

Key Insights

1. 60-80% Optimization as the Sweet Spot

  • Easy to achieve with reasonable effort
  • High efficiency in terms of cost-benefit ratio
  • Realistic and practical range for most business contexts

2. Environment-Specific Optimization Strategy

Stable Environment → Minimal optimization sufficient
Volatile Environment → 60-80% optimization optimal

3. The 100% Optimization Trap

  • Universally inefficient across all environments
  • Very difficult to achieve with no efficiency gains
  • Classic example of over-engineering

Practical Application Guide

60% Level: Minimum Professional Standard

  • MVP releases
  • Time-constrained projects
  • Experimental features

70% Level: General Target

  • Standard business products
  • Most commercial services
  • Typical quality benchmarks

80% Level: High-Quality Standard

  • Core business functions
  • Customer-facing critical services
  • Brand-value related elements

Business Implementation Framework

For Stable Environments:

  • Focus on basic functionality
  • Avoid premature optimization
  • Maintain simplicity

For Volatile Environments:

  • Target 60-80% optimization range
  • Prioritize adaptability over perfection
  • Implement iterative improvements

Conclusion: Philosophy of Practical Optimization

This framework demonstrates that “good enough” often outperforms “perfect” in real-world scenarios. The 60-80% optimization zone represents the intersection of achievability, efficiency, and business value—particularly crucial in today’s rapidly changing business landscape. True optimization isn’t about reaching 100%; it’s about finding the right balance between effort invested and value delivered, while maintaining the agility to adapt when requirements inevitably change.
(!) 60-80% is just a number. The best number is changed by …

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