📚 Year 9 Edexcel Computer Science: Case Study Practical Drills | Year 9 Edexcel 计算机：案例分析实战演练
In Year 9 Edexcel Computer Science, applying your knowledge to real-world scenarios is a vital skill. This article presents a series of practical case study drills that cover key topics such as computational thinking, data representation, networking, cybersecurity, algorithms, and ethical considerations. Each drill will guide you through analysing a problem, applying relevant concepts, and proposing solutions, helping you prepare for exams and coursework.
在 Year 9 Edexcel 计算机科学中，将知识应用于真实场景是一项关键能力。本文提供一系列案例分析实战演练，涵盖计算思维、数据表示、网络、网络安全、算法和伦理考量等核心主题。每个演练将引导您分析问题、应用相关概念并提出解决方案，帮助您为考试和课程作业做好准备。
1. Computational Thinking and Maze Navigation | 计算思维与迷宫导航
A robotics club wants a program that allows a small robot to escape from any simply connected maze. The robot can only sense walls immediately ahead and to its sides. Your task is to design an algorithm using computational thinking techniques.
一个机器人俱乐部想要一个程序，让小型机器人能逃出任何简单连通的迷宫。机器人只能感知正前方和两侧的墙壁。你的任务是运用计算思维技术设计一个算法。
Begin with decomposition: break the problem into smaller parts such as reading sensor input, deciding a move, and repeating until the exit is reached. The maze can be modelled as a grid where each cell has four possible walls.
从分解开始：将问题拆分为读取传感器输入、决定移动、重复直到抵达出口等小部分。迷宫可以建模为一个网格，每个单元格有四面可能的墙。
Pattern recognition helps us see that the right-hand rule (always keep your right hand on the wall) solves any simply connected maze. We recognise that this pattern works because the robot will eventually explore all paths without looping infinitely.
模式识别帮助我们看出右手法则（始终让右手贴着墙壁）可以解决任何简单连通迷宫。我们识别出这种模式之所以有效，是因为机器人最终会探索所有路径而不会无限循环。
Next, we apply abstraction to ignore irrelevant sensory details and focus only on the presence or absence of walls. We design a set of rules:
接下来，我们运用抽象忽略无关的传感器细节，只关注墙的存在与否。我们设计一组规则：
If there is no wall on the right, turn right and move forward.
如果右侧没有墙，向右转并前进。
Else if there is no wall ahead, move forward.
否则，如果前方没有墙，则前进。
Else if there is no wall on the left, turn left and move forward.
否则，如果左侧没有墙，向左转并前进。
Else turn around (180 degrees).
否则，掉头（180 度）。
The algorithm is a clear example of how decomposition, pattern recognition and abstraction lead to a simple, reliable solution. It can be written as pseudocode and then implemented in a language like Python.
该算法是分解、模式识别和抽象如何引出简单可靠方案的清晰示例。它可以被写成伪代码，然后用 Python 等语言实现。
2. Data Representation and Colour Codes | 数据表示与颜色代码
A web designer is working on a site and needs to understand exactly how hexadecimal colour codes determine the appearance of elements. You are given the colour code #A5FF3C and must explain what it means in terms of red, green and blue intensities.
一位网页设计师正在开发网站，需要准确理解十六进制颜色代码如何决定元素的外观。你拿到颜色代码 #A5FF3C，需要解释它在红、绿、蓝色强度方面的含义。
Hexadecimal is a base-16 number system that uses digits 0–9 and letters A–F. Each pair of hex digits represents the intensity of one colour channel. For #A5FF3C, the red channel is A5, green is FF and blue is 3C.
十六进制是以 16 为基的数制，使用数字 0–9 和字母 A–F。每对十六进制数字代表一个颜色通道的强度。对于 #A5FF3C，红色通道为 A5，绿色为 FF，蓝色为 3C。
We can convert these hex values to decimal to understand the intensity on a 0–255 scale:
我们可以将这些十六进制值转换为十进制，以理解 0–255 范围的强度：
A5₁₆ = (10 × 16) + 5 = 165
the red intensity is 165 out of 255. Similarly, FF₁₆ = 255 and 3C₁₆ = (3 × 16) + 12 = 60.
因此红色强度为 165（满值 255）。类似地，FF₁₆ = 255，3C₁₆ = (3 × 16) + 12 = 60。
This colour is a bright yellowish-green because green is at maximum, red is medium-high and blue is low. Understanding such conversions helps in image compression and digital graphics processing.
这个颜色是明亮的黄绿色，因为绿色最大，红色中高，蓝色较低。理解此类转换有助于图像压缩和数字图形处理。
3. Hardware Selection for Gaming Performance | 游戏性能的硬件选择
A student wants to upgrade their desktop computer to run the latest AAA games smoothly. The existing PC has a dual-core processor, integrated graphics, 4 GB RAM and a 500 GB HDD. Identify the key hardware bottlenecks and recommend replacements.
一名学生想升级台式电脑以流畅运行最新的 3A 游戏。现有电脑配备双核处理器、集成显卡、4 GB 内存和 500 GB 机械硬盘。识别关键的硬件瓶颈并提出更换建议。
The most obvious bottleneck is the integrated graphics processor (GPU), which shares system memory and lacks dedicated video RAM. A dedicated graphics card with at least 4 GB VRAM, such as an NVIDIA GTX 1650, would dramatically improve frame rates.
最明显的瓶颈是集成图形处理器 (GPU)，它共享系统内存且缺乏专用显存。一块至少配备 4 GB 显存的独立显卡（例如 NVIDIA GTX 1650）将极大提升帧率。
RAM is also insufficient: modern games recommend 8 GB or more. Upgrading to 16 GB DDR4 RAM ensures that the system does not rely heavily on slower virtual memory.
内存也不足：现代游戏推荐 8 GB 或更多。升级到 16 GB DDR4 内存可确保系统不过度依赖较慢的虚拟内存。
The storage is an HDD, which causes long loading times. Replacing it with a 500 GB solid-state drive (SSD) will reduce boot and game loading times significantly, since SSDs have much faster read/write speeds.
存储是机械硬盘，导致加载时间长。将其更换为 500 GB 固态硬盘 (SSD) 将显著减少启动和游戏加载时间，因为 SSD 的读写速度要快得多。
The dual-core processor may still be adequate for many games if the other bottlenecks are removed, but a quad-core CPU would provide a better experience for CPU-intensive titles.
双核处理器在解决其他瓶颈后对许多游戏可能仍然够用，但四核 CPU 将为 CPU 密集型游戏提供更好的体验。
4. Network Design for a Small School | 小型学校网络设计
A small primary school requires a new local area network (LAN) to connect 50 devices across two buildings. They need file sharing, printer access, and internet connectivity with adequate security. Propose a suitable network topology and hardware.
一所小型小学需要一个新的局域网 (LAN)，连接两栋楼中的 50 台设备。他们需要文件共享、打印机访问和互联网连接，并且要有足够的安全性。提出合适的网络拓扑和硬件。
A star topology is recommended: all devices connect to a central switch. Each building should have a 24-port switch, and the two switches are linked via a high-speed backbone cable. This layout isolates faults easy to manage.
推荐使用星型拓扑：所有设备连接到中央交换机。每栋楼应有一台 24 口交换机，两台交换机通过高速骨干线缆相连。这种布局隔离故障，易于管理。
For internet access, a router with a built-in firewall connects to the ISP. The firewall filters incoming and outgoing traffic, helping to prevent unauthorised access. An additional wireless access point can be added for Wi-Fi devices.
对于互联网接入，一台带内置防火墙的路由器连接到 ISP。防火墙过滤进出流量，有助于防止未授权访问。可以额外添加无线接入点为 Wi-Fi 设备服务。
IP addressing should be assigned statically for shared devices like printers and servers, while student workstations can use DHCP from the router for automatic configuration.
对于打印机和服务器等共享设备，应静态分配 IP 地址，而学生工作站可以使用路由器提供的 DHCP 进行自动配置。
Network security should include strong passwords, MAC address filtering, and regular firmware updates. User accounts on the server can control access to shared files.
网络安全应包括强密码、MAC 地址过滤和定期固件更新。服务器上的用户账户可以控制对共享文件的访问。
5. Cybersecurity Incident Response: Ransomware | 网络安全事件响应：勒索软件
An employee at a small company clicks a link in a suspicious email and soon receives a message demanding a ransom to unlock their files. The entire accounting department's shared folder appears encrypted. Outline an incident response plan.
一家小公司的员工点击了一封可疑邮件中的链接，不久后收到一条勒索信息，要求支付赎金以解锁文件。整个会计部门的共享文件夹似乎被加密了。概述一份事件响应计划。
The first step is to isolate the infected machine immediately by disconnecting its network cable and turning off Wi-Fi. This prevents the ransomware from spreading to other devices on the network.
第一步是立即隔离受感染的计算机，断开其网线并关闭 Wi-Fi。这可以防止勒索软件传播到网络上的其他设备。
Next, alert the IT support team and management. Do not pay the ransom—there is no guarantee files will be restored and payment encourages further crime. Report the incident to national cybersecurity authorities or the police.
接下来，通知 IT 支持团队和管理层。不要支付赎金——不能保证文件会被恢复，而且支付会助长犯罪。向国家网络安全机构或警方报告事件。
Restore the encrypted files from the most recent offline backup. If backups are regularly taken and stored offsite, the damage can be largely reversed. After restoration, run a full antivirus scan and update all software.
从最近的离线备份恢复被加密的文件。如果定期进行备份并异地存储，损失可以基本挽回。恢复后，运行完整的防病毒扫描并更新所有软件。
Finally, conduct staff training to recognise phishing emails and reinforce the importance of not clicking unknown links. Implement email filtering and stronger endpoint protection.
最后，对员工进行培训，识别钓鱼邮件，并强调不点击陌生链接的重要性。实施邮件过滤和更强的端点防护。
6. Comparing Search Algorithms Efficiency | 比较搜索算法的效率
You are given a sorted array of numbers: [2, 5, 8, 12, 16, 23, 38, 45, 56, 72]. A program needs to check if the number 45 is present. Compare linear search and binary search by counting the number of comparisons needed.
给定一个有序数组：[2, 5, 8, 12, 16, 23, 38, 45, 56, 72]。一个程序需要检查数字 45 是否存在。通过计算所需的比较次数来比较线性搜索和二分搜索。
A linear search checks each element in order, starting from index 0. It will compare 45 with 2, 5, 8, 12, 16, 23, 38, 45 and stop after 8 comparisons.
线性搜索从头开始依次检查每个元素。它将 45 与 2、5、8、12、16、23、38、45 比较，并在 8 次比较后停止。
Binary search repeatedly divides the sorted array in half. First, compare 45 with the middle element (index 4: 16). Since 45 > 16, look at the right half [23, 38, 45, 56, 72]. The new middle is 45 itself—found after 2 comparisons.
二分搜索反复将有序数组分成两半。首先，将 45 与中间元素（索引 4：16）比较。由于 45 > 16，查看右半部分 [23, 38, 45, 56, 72]。新的中间元素就是 45——仅需 2 次比较找到。
Time complexity analysis:
时间复杂度分析：
Linear search: O(n) – worst case checks all elements.
Binary search: O(log n) – halves the search space each time.
For large datasets, binary search is far more efficient, but it requires the data to be sorted first. This case demonstrates why algorithm choice matters in software development.
对于大数据集，二分搜索效率高得多，但它要求数据预先排序。这个案例说明了在软件开发中算法选择为何重要。
7. Designing a Mobile App Prototype | 设计移动应用原型
A school wants to create a homework tracker app for students and teachers. Students submit assignments, teachers mark and return them. Use principles of user interface (UI) design and the software development lifecycle to plan a prototype.
一所学校想为学生和教师创建一款作业跟踪应用。学生提交作业，老师评分并返回。运用用户界面 (UI) 设计原则和软件开发生命周期来规划一个原型。
Start with a requirement analysis: identify stakeholders (students, teachers, admin), functional needs (upload files, view deadlines, grade assignments) and non-functional needs (secure logins, fast loading, easy navigation).
从需求分析开始：识别利益相关者（学生、教师、管理员），功能性需求（上传文件、查看截止日期、批改作业）以及非功能性需求（安全登录、加载快速、导航简单）。
Design a low-fidelity wireframe on paper or using digital tools. For the student view, include a dashboard with upcoming deadlines, a list of subjects, and a submission button. For the teacher view, show a class list and a grade entry screen.
在纸上或用数字工具设计低保真线框图。对于学生视图，包含一个带有即将到来截止日期的仪表盘、学科列表和提交按钮。对于教师视图，显示班级列表和成绩录入页面。
Follow an iterative approach: build a basic prototype, test it with a few users, gather feedback, and improve. This mirrors the agile methodology, where software is developed in small cycles.
采用迭代方法：构建基本原型，与少数用户测试，收集反馈并改进。这反映了敏捷开发方法，即软件以小周期开发。
Evaluate the prototype against usability heuristics: visibility of system status, user control, consistency, error prevention, and aesthetic design. This ensures the final product meets users' real needs.
根据可用性启发式原则评估原型：系统状态可见性、用户控制、一致性、防错和美观设计。这确保了最终产品满足用户的实际需要。
8. Ethical Issues in Social Media Algorithms | 社交媒体算法的伦理问题
A social media platform uses algorithms to personalise users’ news feeds. While engagement has increased, critics argue it creates ‘filter bubbles’ and can be exploited for spreading misinformation. Analyse the ethical concerns and suggest solutions.
一个社交媒体平台使用算法来个性化用户的新闻推送。虽然参与度增加了，但批评者认为它制造了“信息茧房”，并且可能被利用来传播错误信息。分析相关伦理问题并提出解决方案。
Filter bubbles occur because the algorithm prioritises content similar to what a user already likes, reducing exposure to diverse viewpoints. This can polarise opinions and weaken democratic debate.
信息茧房的产生是因为算法优先展示与用户已喜欢内容相似的内容，减少了接触多元观点的机会。这可能导致观点极化并削弱民主讨论。
Data privacy is another major concern: the platform collects massive amounts of personal information to train its algorithms. Users often are not fully aware of what data is collected or how it is used.
数据隐私是另一个主要关切：平台收集大量个人信息来训练算法。用户往往不完全了解收集了哪些数据或如何使用这些数据。
From a legal standpoint, regulations like the UK Data Protection Act 2018 and GDPR require transparent data processing and give users the right to access their data. The platform must provide clear consent options and avoid deceptive design patterns.
从法律角度看，英国《2018 年数据保护法》和 GDPR 等法规要求透明的数据处理，并赋予用户访问其数据的权利。平台必须提供明确的同意选项，避免欺骗性设计模式。
Potential solutions include: giving users more control over their recommendation settings, adding a ‘view from other perspectives’ feature, regularly auditing algorithms for bias, and investing in digital literacy education to help users critically evaluate content.
可能的解决方案包括：让用户对推荐设置有更多控制权，添加“视角切换”功能，定期审查算法偏见，以及投资数字素养教育以帮助用户批判性地评估内容。
Published by TutorHao | Computer Science Revision Series | aleveler.com
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