CoLink: Global Compression and Knowledge Linking for Multi-Turn Dialogue Modeling
Authors: Lian Yan, Zhenbo Xia, Haotian Wang, Chen Tang, Yi Guan, Jie Liu, Jingchi Jiang
Organizations: Research Center of Language Technology, Faculty of Computing, Harbin Institute of Technology, Harbin, Heilongjiang 150001, China · Institute for Advanced Algorithms Research, Shanghai, 201306, China · Research Center of Artificial Intelligence of Things, Faculty of Computing, Harbin Institute of Technology, Harbin, Heilongjiang 150001, China, and also with the National Key Laboratory of Smart Farm Technologies and Systems, Harbin, Heilongjiang 150001, China
Extracting salient information from long-horizon dialogue histories remains a significant challenge for Large Language Models (LLMs) due to the restricted context windows and efficient retrieval challenges. Current methods typically rely on history organization or local token-level optimization, suffering from information loss, retrieval redundancy, and myopic attention. Inspired by the view in cognitive science that dialogue constitutes sense-making and memory association, we propose CoLink, a framework that enhances LLMs' global context awareness in domain-specific multi-turn dialogues through information linking and compression. CoLink first clusters historical contexts into topic graphs to establish cross-semantic associations with external knowledge. Guided by the adaptive control of thought, it then retrieves and activates knowledge via synergizing semantic relevance and graph-structural topology. Crucially, to achieve effective compression of history and knowledge, we ground multi-turn dialogues in information theory and derive a principled optimization objective for extracting the core sense-making information. Coupled with a competitive slot mechanism, CoLink condenses the global context into dedicated memory and knowledge slots, efficiently distilling lengthy, redundant inputs into an extremely compact latent representation. Extensive empirical results on both public and our MMD datasets validate CoLink's superiority and generalizability in knowledge linking and sense modeling.
Figures & tables
Fig. 1: Rigid Retrieval & Local Tokens vs. History Compression in CoLink.
Fig. 2: Cognitive isomorphism between human memory mechanisms and the CoLink framework. The diagram illustrates two key biological parallels: (1) Associative Retrieval: Analogous to the hippocampus retrieving episodic memories to activate long-term cortical knowledge, CoLink constructs topic graphs to link historical contexts with external knowledge, dynamically activating relevant facts via the semantic relevance and structural linkage importance. (2) Abstract Encoding: Just as the human brain stores highly abstract semantic schemas rather than verbatim textual records, CoLink employs an global competitive compression strategy. This rigorously distills raw history and knowledge streams into compact Memory/Knowledge slots, mirroring the brain’s efficiency in retaining core semantics while filtering redundancy.
Fig. 3: The framework of CoLink.
Fig. 4: Example of the data construction process.
Dataset
Domain
Lang.
# Samples
# Diseases
Avg. Turns
Debate Turns
MMD
Medical
Chinese
2,370
37
8.09
2.77
CMtMedQA
Medical
Chinese
5,993
14
8.85
–
TABLE I: Dataset statistics.
Hyperparameter
Description
Value
E1
Stage 1 Epochs
10
E2
Stage 2 Epochs
10
η1
Stage 1 Learning Rate
5e−5
η2
Stage 2 Learning Rate
1e−5
wd
Weight Decay
0.01
B
Batch Size
4
TABLE II: Hyperparameter settings for CoLink.
Method
MMD (%)
CMtMedQA (%)
B1
B2
B3
B4
R1
R2
RL
BS
B1
B2
B3
B4
R1
R2
RL
BS
MemoryBank
19.41
8.55
4.47
2.32
23.31
5.24
14.98
68.83
27.20
14.20
8.34
4.90
29.69
9.06
21.67
73.75
NV-embed
17.77
8.10
4.22
2.31
23.34
5.60
15.35
68.22
23.82
12.18
7.14
4.19
27.57
8.17
20.09
72.10
StreamLLM
0.38
0.06
0.03
0.02
1.75
0.02
1.69
45.97
0.60
0.11
0.06
0.04
3.70
0.21
0.99
46.08
GraphRAG
16.45
6.64
3.24
1.65
21.57
4.37
14.15
67.91
24.10
12.02
6.90
3.94
27.25
7.64
19.45
72.41
CCA
8.62
2.99
1.46
0.78
13.61
2.07
8.75
64.14
4.14
1.32
0.56
0.27
11.39
1.49
7.98
58.67
TABLE III: The comparative results. We highlight the best performance. B, R, and BS stand for BLEU, Rouge, and Bertscore, respectively.
Method
MMD
CMtMedQA
History/Knowledge Processing Time (ms)
GPU Memory (MB)
Compression Ratio
History/Knowledge Processing Time (ms)
GPU Memory (MB)
Compression Ratio
MemoryBank
2113.57
/
0.6388
4521.04
/
0.4884
NV-embed
218.41
27674.82
0.8095
202.69
27612.20
0.7732
StreamLLM
/
3050.95
0.9665
/
3064.59
1.0000
GraphRAG
41511.27
/
2.8946
47679.49
/
2.4866
CCA
/
3679.53
0.8903
/
3724.54
1.0000
TABLE IV: Comparison of online resource consumption and compression ratios.
Input Encode
BLEU (%)
ROUGE (%)
BS (%)
B1
B2
B3
B4
R1
R2
RL
Base(Full History)
18.21
11.02
7.84
4.66
30.03
10.13
15.31
69.38
Base(Summary History)
21.89
13.11
7.65
5.57
32.36
11.21
17.09
70.46
Memory Slot(Ours)
24.21
14.04
8.60
5.02
31.82
10.44
17.70
70.25
TABLE V: Transfer performance of CoLink on Llama-3.2-3B, involving only first-stage memory slot training.
Input Encode
BLEU (%)
ROUGE (%)
BS (%)
B1
B2
B3
B4
R1
R2
RL
Base(Full History)
23.28
12.67
7.97
5.12
28.72
8.62
25.60
74.96
Base(Summary History)
18.18
9.78
6.03
3.75
30.38
9.02
27.03
74.16
Memory Slot(Ours)
38.49
23.16
15.59
10.48
39.42
14.52
35.33
78.68
TABLE VI: Transfer performance of CoLink on English open-domain multi-turn dialogue dataset.
Method
BLEU (%)
ROUGE (%)
BS (%)
B1
B2
B3
B4
R1
R2
RL
CoLink (stage1)
26.40
13.40
7.88
4.54
29.09
8.63
20.52
73.30
TABLE VII: Generalization across different datasets.
Fig. 5: Attention and loss saliency of summary history and memory slots towards the query and next-token prediction.
Method
Human
LLM-as-Judge
Accuracy & Professionalism
Informativeness
Contextual Coherence
Overall
Accuracy & Professionalism
Informativeness
Contextual Coherence
Overall
MemoryBank
3.77
3.08
4.28
3.71
3.94
3.49
4.46
3.96
NV-embed
3.56
2.72
4.14
3.47
3.82
3.24
4.31
3.79
GraphRAG
3.54
2.44
4.65
3.54
3.21
2.56
4.42
3.40
CCA
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
MemTree
2.80
1.84
4.40
3.01
3.78
3.03
4.70
3.84
TABLE VIII: Human and LLM-as-a-Judge evaluation on Accuracy & Professionalism, Informativeness, and Contextual Coherence.
History Len.
MMD (%)
CMtMedQA (%)
B1
B2
B3
B4
R1
R2
RL
BS
B1
B2
B3
B4
R1
R2
RL
BS
CoLink(Ours)
27.52
13.87
7.66
4.10
31.63
8.64
19.26
72.84
31.62
18.02
11.74
7.62
34.28
12.31
25.50
75.36
w/o Memory Slots
24.13
11.42
6.26
3.35
28.35
7.08
17.87
70.94
28.73
15.83
9.96
6.18
31.89
10.81
23.74
74.33
w/o Knowledge Slots
27.61
13.82
7.71
3.96
31.88
8.54
19.33
72.78
30.08
17.00
10.91
6.97
32.73
11.62
24.01
74.81
TABLE IX: Performance after ablating memory slots and knowledge slots.
Method
Accuracy (%)
Base
79.08
+Full Knowledge
82.00
+Summary Knowledge
59.83
CoLink (Knowledge Slots)
90.37
TABLE X: Performance Comparison on the GMD Dataset with Precisely Aligned Knowledge Graphs.
Method
BLEU (%)
ROUGE (%)
BS (%)
B1
B2
B3
B4
R1
R2
RL
CoLink (stage1)
23.21
10.96
5.66
3.01
27.90
6.84
17.60
70.88
w/o Lrec
16.74
6.60
3.24
1.73
21.36
3.88
14.36
67.84
w/o LKL
25.65
11.81
5.99
3.15
29.27
6.81
17.33
71.36
w/o Lpred
17.13
6.74
3.23
1.60
22.54
4.19
15.25
67.73
TABLE XI: Ablation study on different loss terms.
α
BLEU (%)
ROUGE (%)
BS (%)
B1
B2
B3
B4
R1
R2
RL
10.0
20.30
8.74
4.40
2.18
24.30
5.11
15.74
69.28
0.1
21.32
9.40
4.96
2.63
26.46
5.95
16.73
69.57
TABLE XII: The performance after scaling LKL .
Fig. 6: Training loss trajectories under different ablation settings.
Input Encode
BLEU (%)
ROUGE (%)
BS (%)
B1
B2
B3
B4
R1
R2
RL
Layer 0 Hidden State
15.86
6.00
2.87
1.41
21.07
3.68
14.79
67.42
nn.embedding
17.14
6.74
3.21
1.60
21.64
3.67
14.43
67.93
Last Layer Hidden State
23.21
10.96
5.66
3.01
27.90
6.84
17.60
70.88
TABLE XIII: Impact of Input Encoding Methods on Model Performance
Fig. 7: Comparison of generations for a case across different models.
Method
BLEU (%)
ROUGE (%)
BS (%)
B1
B2
B3
B4
R1
R2
RL
History Cluster
25.18
11.56
5.86
3.09
28.98
6.76
17.75
71.18
Full History
25.58
11.86
6.15
3.20
28.88
6.86
17.61
71.34
TABLE XIV: Performance comparison between compressing Retrieved Topic Clusters and Full History.
Department of Computer Science and Engineering, The Hong Kong University of Science and Technology, Hong Kong · NVIDIA AI Technology Center, NVIDIA · University of Tsukuba, Japan +1