## 1 Introduction  
### Background and Purpose  
As the global population continues to age rapidly, many countries have been implementing various policies and programs to enhance older adults' quality of life and support healthy aging [1, 2, 3, 4]. Asia covers approximately 30% of Earth's total land area and houses more than 60% of the world's population. This high population density can potentially accelerate the aging trend [5]. In South Korea, elderly welfare has become a substantial social concern owing to its rapidly aging population [6, 7]. The government is actively working to improve the quality of life and promote the welfare of senior citizens via diverse welfare policies and systems [8, 9]. The proportion of the elderly population aged 65 or older in South Korea has been increasing rapidly since the early 2000s [10]. By March 2024, this age group accounted for over 19% of the country's population [11]. Based on these trends, South Korea is projected to become a super-aged society by 2025, and the elderly population is expected to comprise approximately 30% of the total population by 2036 [12]. In particular, Busan--one of the major cities in South Korea--is experiencing the aging phenomenon more acutely than other regions [13; 14]. The city has become a super-aged society earlier than other metropolitan areas, as over 20% of its population has been aged 65 and above since 2022 [15]. Consequently, the demand for elderly welfare in the community is increasing rapidly [16; 17; 18]. Busan's aging population has a substantial impact on the city's economic and social structure, and the need for various welfare policies and programs to support health care, social participation, financial independence, and sustainable community development for older adults in their later years is becoming increasingly emphasized [19; 20]. The city of Busan is actively operating various senior welfare facilities to address the challenges posed by a rapidly aging population. Among these, senior citizen centers provide essential community spaces where older adults can socialize, engage in hobbies, participate in joint workshops, exchange information, and enjoy leisure activities [21; 22; 23]. In addition, these centers play a pivotal role in promoting social participation among senior citizens and strengthening their connections to the community, thereby reducing feelings of social isolation and enhancing their quality of life [24; 25; 26]. Furthermore, as opposed to merely serving as recreational spaces, senior citizen centers fulfill important welfare functions that promote physical health, emotional stability, and social interaction among older adults [27; 28; 29]. In large cities such as Busan, where the aging population is increasing rapidly, senior citizen centers are indispensable. They can serve as models for establishing and implementing senior welfare policies in other urban areas. However, to date, domestic studies focusing on senior citizen centers have primarily examined physical conditions or satisfaction related to welfare policies, spatial planning, physical accessibility, facility satisfaction, and operational programs; psychological factors such as motivation for use remain underexplored [14; 21; 22; 23; 24; 25; 26; 27; 28; 29]. In particular, empirical studies that comprehensively examine motivations, frequency of use, and satisfaction are urgently needed as these variables significantly influence the utilization of senior citizen centers. Furthermore, the later years of older adults are affected by various factors, including government policies, the diversity of services available, and the operations of private organizations [31; 32]. Motivations for using senior citizen centers differ depending on the type of eldercare system selected by older adults. The eldercare system can be categorized into home-based, community-based, and institutional care models [33; 34; 35], and the welfare needs and usage patterns of older adults may vary according to these types.