Initialism for system health management

• Monitoring, fault diagnosis, and control of a system's condition

系统健康管理的首字母缩写

• 对系统状态的监测、故障诊断与控制

Initialism for simple harmonic motion

• Periodic oscillation with restoring force proportional to displacement

简谐运动的首字母缩写

• 恢复力与位移成正比的周期性振动

Internet initialism meaning shake my head

• Expresses disbelief, disappointment, or mild disapproval

网络缩写，表示摇头

• 表达不信、失望或轻微的不赞同